how to test cruise control actuator

Fixing Faulty Cruise Control

Alarmingly, the speedometer needle steadily winds down from 75 mph toward 50. Just as you uncurl your feet and try to accelerate back to traffic speeds, the vehicle downshifts with a lurch and abruptly climbs back to over 80 mph. So you tap the brakes and disengage the cruise control to avoid a conversation with one of the many law enforcement officers lurking behind every other billboard. Toggling the Resume switch settles things down, holding to a legal speed on both the uphill and downhill sections of the interstate. The kids in the back seat have stopped threatening to throw up, too. Then you look in your mirror 20 miles later and see the lights. Red and blue flashing lights. You're doing over 85 mph and, odds are, Smokey isn't going to believe you have the cruise set to 70. Time to find out why your cruise control has a mind of its own.

IT'S NOT A BUG, IT'S A FEATURE Does your cruise control fall out of engagement partway up steep hills? Actually, it will normally drop out if the engine has to work too hard, mainly because after a while there isn't enough vacuum left to pull in the servo after sustained near-wide-open-throttle. You'll just have to put your foot into it. Downshifting helps.

Does your Japanese car not remember the set speed after tollbooths? Unlike most American and European cars, some Toyotas and Hondas are designed not to remember their set speed if the vehicle speed falls below 25 mph, and you're supposed to accelerate the vehicle to your set speed and hit the Set button again. Annoying, but that's the way they were designed.

Do you have to ride the brakes on longer downhills to keep from building up excess speed? That's normal too. The cruise control only has authority to reduce engine speed to idle. It doesn't activate the brakes. Modern cars, in an attempt to improve mileage, have very tall gear ratios, low-friction engine designs, low-rolling-resistance tires and optimized aerodynamics. That long downgrade outside of town may have accelerated your '60s-era Pontiac to only a couple of miles per hour above legal. But, it may well propel your new economy car to blatantly illegal velocities unless you intervene by braking or downshifting.

WHAT'S THAT HISS?: Most common cause of erratic cruise control? Vacuum leaks caused by deteriorated hoses.

SMOOTH AND STEADY Cruise control on your vehicle is a terrific device. It substantially reduces the driver's workload on longer trips, and can save substantial amounts of fuel and expense over the life of the vehicle--until it stops working.

We'll get to the scenario of not holding a steady speed later, but here are a couple of things to check immediately if the cruise control is on strike.

Does the Cruise icon on the dash light up when you turn the switch on? Duh. Check the fuse. You may need to look in the owner's manual to see which one if it's not tagged on the fuse box cover. An aftermarket cruise may have an inline fuse holder in the wiring to the controller.

If there is power to the system, the next check is the brake lights. Brake lights? Yup, cruise controls have a switch to toggle them off when you touch the brake pedal, and many use the same switch as the brake lights. If one of the brake lights has failed, the cruise control thinks the brakes are on all the time and won't come on. Same result if the switch is incorrectly adjusted or broken or jammed. Wait, there's more--if your vehicle has a manual transmission, there's a similar switch on the clutch pedal. You may need to break out a test light or multimeter to verify the function of this array of switches. These switches usually are normally closed switches, and close their contacts when the pedal is depressed. We've seen several cases of intermittent cruise control dropout caused by a brake light switch that was adjusted very tight. Any small bump would jiggle the brake pedal down far enough to toggle the brake lights on for a brief instant--long enough to shut down the cruise. Adjusting the switch to specs (usually so the brake lights come on after the pedal travels 1/2 in.) fixed it.

Once you verify all of these things, it's time to look for more subtle causes. Check underhood. Inspect the linkage between the cruise control actuator and the throttle. It may be as simple as a toilet-tank bead chain or a separate throttle cable with its own actuator cam to the throttle body. Look for disconnected or damaged wiring to the controller or actuator, particu-larly if it's an aftermarket system, which may have been installed by someone with poor mechanical skills.

Another obvious failure point is the vacuum line to the actuator. If it has fallen off, there's no vacuum to the actuator and no force can be applied to the throttle. We'll get ahead of ourselves here and mention that a vacuum line that looks fine may have a subtle leak caused by aging, brittle rubber or connections that don't seal well. A lot of the cruise controls we've seen with issues in regulating their speed correctly are fixed by simply replacing all the vacuum lines between the servo, vacuum reservoir (if there is one) and the intake manifold vacuum supply.

WHOA, NELLIE!: If your brake light switch is incorrectly adjusted, your cruise control may not lock in. A burned-out brake light can do the same.

WHAT'S THIS THING?: The cruise control servo motor could be anywhere in the engine compartment.

CONTROL ISSUE WITH YOUR SERVO There are two main components of the cruise control system: the controller and the servo.

The controller integrates all the inputs and tells the servo how far to actuate the throttle plates. Normally, there is no way you can service this item, so if you trace a problem to the controller, you'll have to buy a new one. A bad controller probably will require a service manual for specific diagnostics. You'll also need a scan tool to access any computer trouble codes to boot.

The servo does the work of moving the throttle blades to speed up the vehicle. Conventional systems are actuated by manifold vacuum. Check the linkage from the servo to the throttle to ensure it's properly hooked up and not binding or sticky. Inside the servo is a diaphragm that moves to pull on the linkage. Some older systems, used on cars or trucks that don't have throttle-position sensors, may have a rod that moves in and out of a magnetic coil to tell the controller the throttle position. There are also two electrically operated solenoid valves. One valve admits vacuum to the diaphragm chamber to add more throttle. The other bleeds air back into the chamber to reduce throttle. Normally, they will never be open at the same time, so if one is sticky or leaking, cruise control operation will be erratic at best. Check for leakage with a handheld vacuum pump. A leaky valve may benefit from a quick shot of silicone spray.

Diesels and some late models may use a servo that is completely electrical. These usually are mounted on the fenderwell or firewall, and are connected to the throttle by a second throttle cable. Other than keeping the cable lubricated and properly adjusted, there's not much to fiddle with. As always, check the shop manual for specifics on your vehicle.

Many late-model cars have throttle plates connected directly to an actuator controlled by the engine management computer. There is no physical connection between your right foot and the throttle blades (Scary, eh?), and there may or may not be a separate cruise control servo or controller.

HOW FAST WAS I GOING, OFFICER? If you still have no engagement, there may be an issue with the cruise control's speed input. Modern cars use information from the ABS's vehicle speed sensor (VSS) because the engine-management computer needs to know road speed. If your Check Engine light is on, the cruise may not work, especially if the VSS is malfunctioning. Older vehicles may use speed information from the speedometer. Aftermarket systems may resort to a ring of magnets clamped to a driveshaft or axle shaft, with a magnetic coil positioned nearby. If the magnets have fallen off or the coil has been smashed by a rock or road debris, there's no speed data for the controller.

URBAN LEGEND The legend has been related to us by all manner of people, including a couple of state police officers. Using the cruise control in rainy or slick conditions will make your car speed up uncontrollably, until you lose control and crash. It's a myth. Engaging the cruise will not make the car speed up. The cruise will attempt to maintain a steady speed. If the wheels lose traction and the car starts to slow down, the cruise will speed up the engine to attempt to accelerate back to the set speed. This will make the drivewheels spin more briskly. The vehicle speed will go slower, regardless of how furiously the wheels spin. If you have a rear-wheel-drive car, the effect is to destabilize the vehicle, and you probably will spin out unless the vehicle regains traction in a reasonable length of time. A front-wheel-drive car with spinning tires will attempt to continue in a more or less straight line--which will make steering control dodgy at best.

Heavy rain or snow makes use of the cruise control inadvisable, but such conditions certainly won't make your car accelerate to ludicrous speeds while you hang on for dear life. If the cruise is engaged and you perceive a loss of traction, the best bet is to tap the brake to disengage the system, and then add just enough throttle to maintain steering until the vehicle slows down to a more appropriate speed.

WHERE'S THIS THING?: Speed sensor may be buried under the dash near speedo head.

SUCK IT UP: The vacuum reservoir provides an added source of vacuum for those long uphill grades.

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Cruise Control Not Working: Reasons and Quick Fixes

JUMP TO TOPIC

• 0.1 How To Identify and Fix Issues With Cruise Control?
• 0.2 1. Blown Fuse
• 0.3 2. Faulty Brake Switch
• 0.4 3. Malfunctioning Speed Sensor
• 0.5 4. Broken Cruise Control Switch
• 0.6 5. Vacuum Leak
• 0.7 6. Wiring Issues
• 0.8 7. Throttle Actuator Failure
• 1 Can a Faulty Cruise Control System Cause the Toyota Camry Alarm to Go Off?
• 2 Conclusion

How To Identify and Fix Issues With Cruise Control?

1. blown fuse, 2. faulty brake switch.

3. Malfunctioning Speed Sensor

4. broken cruise control switch, 5. vacuum leak, 6. wiring issues, 7. throttle actuator failure, can a faulty cruise control system cause the toyota camry alarm to go off.

A faulty cruise control system can indeed trigger the Toyota Camry alarm. To address this issue, consider some toyota camry alarm troubleshooting tips . First, check if the cruise control switch is stuck or malfunctioning, as this might cause the alarm to go off unexpectedly. Additionally, inspect the vehicle’s wiring and connections related to cruise control. Ensuring proper functioning of these components can help prevent the alarm from being triggered unnecessarily.

• Blown fuses are a common culprit for cruise control failure, and locating and replacing them is relatively easy.
• The brake switch and speed sensor can also cause issues with cruise control, and replacing them requires some expertise.
• A broken cruise control switch can be easily located and replaced, but it’s crucial to ensure compatibility with your vehicle’s system.
• Checking the vacuum system is another critical step in diagnosing cruise control issues , and damaged vacuum lines can be replaced with new ones.
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Troubleshoot Cruise Control

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Hello fellow TN members. I looked at the 3rd/4th gen stickies for cruise control (CC) troubleshooting and only found CC installation. I have a 97 Camry LE 2.2., auto trans. My CC stopped working a couple weeks ago. This seemed to happen the same time my drivers power door lock stopped working, so I'm not sure if they are related. The other locks still work but the drivers door lock has to be operated manually. The problem is that the green cruise light won't even come on. I tried operating the CC assuming the bulb might be bad, but it would not work. 1)I checked all the fuses today. One fuse was out: power-outlet 15A. Since I no longer have fog lights, I took the fog light 15A fuse and used it for the power-outlet. Still no success. 2) I checked the dash bulb and found it working properly. 3) I checked all 3 brake lights, and they're working. 4) I checked for any broken cables/wires that I think are part of the CC system. I did not see anything out of the ordinary. There is a plug that goes into what I think is the CC actuator. Can anyone tell me how to test the system with my multi meter? Is there anything I'm over looking? I have an electronic manual, but there is no heading for CC. What chapter is CC covered in? edit: The check engine light is not on. Thanks for your attention. Tom  

On a 94 Camry hand book, the CC can be found on the 'Body Electrical System' chapter. I am not sure how much it differs from the 97, however.  

Strangely enough, I have 2 chapters, one a "body electrical" and another a "body electrical body", 135 pages and 298 pages respectively. There are mentions of CC in reference to electrical troubleshooting.  

I looked at an electronic copy of a 99 manual and what you're looking for is in the 'Wire' chapter.  

I found the wire chapter and there's more info in the diagnostics chapter too. Lots of reading, got plenty of work ahead.  

Keep us updated! Thanks!  

The CC uses the stop, ecu-ig, and gauge fuses. ... Maybe check the connection to the cruise control actuator. Disconnect the 4 wire black connector ... under the hood ... looks like it is at about 2 o'clock from the transmission dip-stick ...6" or so. Suggest disconnecting the connector and spraying both parts with electrical contact cleaner.  

Have you checked the physical cable connections at the throttle body and cruise control actuator? The actuator is just a motor that rotates and pulls the throttle cable on the throttle body. I made a video on how it works: As for the power door lock, its very likely the actuator is worn and will need to be replaced. Here's my video on that:  

Nice videos, thanks for putting in the effort and uploading! Fuses are good, except the fog light fuse is empty since I no longer have fog lights. The cables to the actuator and throttle seem good. Do you know how to trouble shoot the actuator electrical connector, which pins to test and proper voltage, resistance, etc.? As for the locks, I found out that a couple companies called Mabuchi and Nichibo sell replacement motors for under $10. These are often the cause of power lock failure. The problem I'm having is figuring out which specific one to order before taking the lock assembly apart, since I need to use the car daily and want to have the new part in hand before disassembly.  

Is your speedometer working as usual? Is shifting gears going smoothly? Both of these are part of the cruise control loop and must be working properly. A '97 model year is approaching the lifespan of electrolytic capacitors. There also a printed circuit part called a 'resonator' that can go out after 20 years ... http://www.digikey.com/product-detail/en/ecs-inc/ZTT-4.00MG/X902-ND/8218r2 Cruise control diagram is on the general wiring diagram section. ... Not much other than a schematic diagram though.  

Shifting and speedo working fine at this time. I went through that process last year when the speedo and shifting went awry. I tried to change the resonator but my solder skills were rusty and I was impatient, so it didn't turn out well. I ended up buying a speedo from a local junk yard. It came out of either a 2000 or 2001 model Camry, and no noticeable problems with it since.  

... Just looking at the Cruise Control wiring diagram ... p. 216 ... There is a connection from the neutral safety switch to the cruise control ECU, when the transmission is in drive. ... Thinking that you could pull the plug on top of the NSS, spray it with electrical contact cleaner and make sure it is making good contact with its mating pins. ... Also, if you have never removed the NSS, cleaned it and added new dielectric grease, then that is a good idea every 20 years or so. When you have good electrical contact throughout this section of the wiring diagram, the cruise light should turn on, unless that is, something is bad in the CC ECU.  

I stopped in at the last Radio Shack in town and bought their Contact Cleaner and Lubricant spray. I sprayed it on the CC actuator plug and the NSS plug, both sides. The CC light still isn't coming on. What I did not mention before is that I had grown accustomed to using the CC on an almost daily basis. I have an Ultragauge on the car and I'm able to monitor fuel economy. I got the best fuel economy when I used the CC. The point being, maybe I just wore something out from daily use.  

Take a look at the CC wiring diagram. There is a switch ...internal to the neutral safety switch, that goes to the cruise control ECU. The NSS is located on the lower part of the engine/trans. It has a rubber gasket that loses its seal after so many years and allows water to get inside. You need to R&R the NSS. ... Good chance that will fix the CC. Also, better starting.  

I'm quoting this from a Corolla forum. It may apply to Camrys too. Hope it might help. -SP 1. Turn the ignition switch on 2. Connect terminals Tc and E1 on the diagnostic tower 3. Read the trouble code by counting blinks of the cruise main indicator light: DTC Chart: Continuous blinking: Normal 11 (i.e. 1 blink pause 1 blink): Continuous output to motor acceleration site OR Overcurrent (short) in motor circuit 12 (i.e. 1 blink pause 2 blinks): Overcurrent (short) in magnet clutch circuit OR Open in magnet clutch circuit 13: Open in actuator motor circuit OR Position sensor detects abnormal voltage OR Position sensor signal value does not change when the motor operates 21: Speed signal is not input to the cruise control ECM 23: Actual vehicle speed has dropped by 10 mph or more below the set speed during cruising 32: Short in control switch circuit 34: Voltage abnormality in control switch circuit  

Speedy, thanks for the input. I actually tried this. I wasn't sure if the other port was an older or legacy version of the obd2 diagnostic system. But I did as you suggested and I got a steady blink from the cruise light. My interpretation too, was that it was normal, and the new obd2 system is not throwing out any trouble codes either. I've also verified that the check engine light comes on at startup.  

Before my CC went bad, I had never had to deal with the NSS. I watched some videos and I can understand how after 20 years the internal grease would dry out. So I sprayed the cleaner lube into both sides of the NSS plug. I've never had any problems starting the car in park or neutral. I also checked the backup lights, and they're working fine as well. I have to decide whether to crack open the NSS or pay the dealer the 30 bucks they want. Yes, called them yesterday and thought they would be less reasonable. Work has been slow so I have to balance the whole process with economy in mind.  

Here is the DIY link: http://www.toyotanation.com/forum/1...ral-safety-switch-cleaning-5.html#post8341521 ... materials required are a piece of emery cloth, a packet of dielectric grease, and a can of contact cleaner. Time required, if no problems, about an hour or two. ... just a possibility that it is the cause of the problem.  

OK, here is the 10 month update. Last November my cruise control and horn stopped working. The airbag light was also on. Well, I paid Toyota to trouble shoot it and it turned out the clockspring (spiral cable) was bad. Bought a cheapo on ebay and I'm back in business. Mostly. The airbag connector was different, so the airbag is non operable until I solder the old connector to the new clockspring. Gratefully, the horn and cruise work perfectly. It was pretty aggravating a few months ago to have to make a trip to Miami without a horn. Before this was diagnosed, I had never heard of a clockspring, but it was an easy replacement. I caution others to be careful how they handle the airbag module if they get into this. Also, disconnect the battery long enough to discharge the airbag circuits.  

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Cruise control actuator testing

Started by 1980sdga, 28 November 2011, 09:08 PM

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• Location: Melbourne

Quote from: 1980sdga on 28 November 2011, 09:08 PM Can I apply vacuum to the actuator using a pump and still apply voltage to the pins to test it?  Do the electrics control a vacuum valve inside the actuator?

Big_Richard

Quote from: Major Tom 6.9 on 29 November 2011, 04:16 AM Did you take any photos ?

Quote from: 1980sdga on 29 November 2011, 01:32 PM My cruise was working but it exhibited the symptoms of a bad amp.

Quote I have a vacuum pump/reservoir rig that I used when sorting my ACC and door locks without having to run the engine. I figured I could use it to bench test this accumulator before going to the trouble of installing. I have a 12v power supply but no way to vary the current. Any input on this?

Quote Thanks!  I'm looking forward to seeing some pics of the inside of this thing!

Quote from: koan on 29 November 2011, 03:09 AM

Quote from: koan on 29 November 2011, 02:50 PM I'll do it (after I finish painting a cornice in 4 colours, hanging a few pictures and helping with curtains, the list will probably grow before the weekend - if I'm really really lucky...).

Quote from: Major Tom 6.9 on 03 December 2011, 07:59 AM Its always quite interesting to see how things "got done" in the days prior to the dirt cheap electronics that now rule our world.

Quote from: koan on 02 December 2011, 11:57 PM And guess what!   Dale is away for the weekend so painting, picture hanging and curtains have taken on an exceedingly  low priority koan

Quote from: 1980sdga on 03 December 2011, 10:14 AM Pick the low hanging fruit. Maybe hang a picture.  BE A HERO!

Quote from: 1980sdga on 04 December 2011, 12:22 PM Any advise on adjusting the cable where it connects to the throttle?  For now I have it adjusted so the pad on the cable is just touching the throttle linkage.

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Cruise Control Test Procedure

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Hi! I know there are a lot of cruise control threads in here, but none that I have found seem to answer my questions. The cruise on my 91 Turbo R (3-speed) has not worked in the time that I've had the car. None of the buttons on the gearstalk do anything. I've swapped the ECU for a 2nd hand one that was allegedly OK. The brake lights (the car doesn't have the 3rd upper light) and speedometer work fine. How do I check that the buttons in the stalk do what they're supposed to do? I can't see a way of dismantling it! How do I check the switch in the rat trap? If one presumes that the ECU is OK, the microswitch in the stalk and the second side of the brake switch would be my prime suspects! Cheers Es  

Have you looked over the schematic for the cruise circuit? I'm sure there is a relay involved.  

The_Nuge said: Hi! I know there are a lot of cruise control threads in here, but none that I have found seem to answer my questions. The cruise on my 91 Turbo R (3-speed) has not worked in the time that I've had the car. None of the buttons on the gearstalk do anything. I've swapped the ECU for a 2nd hand one that was allegedly OK. The brake lights (the car doesn't have the 3rd upper light) and speedometer work fine. How do I check that the buttons in the stalk do what they're supposed to do? I can't see a way of dismantling it! How do I check the switch in the rat trap? If one presumes that the ECU is OK, the microswitch in the stalk and the second side of the brake switch would be my prime suspects! Cheers Es Click to expand...

rrtechnical.info/sz/sz80/m8.pdf The only reference I find so far is on page 42 but there is nothing related in the surrounding pages...Is there another resource as detailed as these manuals?  

Those Lucas 6RA relays seem to play a big part in the electrical systems on these cars. I found they are readily available and am adding one to my tool box for diagnostic "swap out" purposes. It's the cheapest part sometimes. The 30amp Bosch relays play a major role too and I've got one of those standing by. Still searching. Flying Spares will rent you their Speed Control Test Box for 100 pounds...ugh  

Hi Guys, @ Wraithman: on US models (and possibly others with the 3rd brake light), there's a relay in the boot / trunk that appears to be significant. On European models the relay socket appears to be bridged. I'll check mine tomorrow, as I can't recall haing seen that! I think the micro switches in the stalk can be checked via either the plug for the ECU or a 6-way plug the must be under the steering column. @ 86BlueSpur: my controls are integrated in the gear shift stalk behind the steering wheel. Es  

The_Nuge said: checked via either the plug for the ECU Click to expand...

Looking at the wiring diagram, this system is very easy to test with a voltmeter or test lamp. Pin 13 - Engine running and gear selector in drive - 12V should be present. Pin 14 - Press set/accel switch - 12V should be present when pressing the switch. Pin 7 - Speed signal, Connect Voltmeter to this pin and drive. I believe that the signal is AC, as you go faster the voltage should increase. Pin 2 - Ground If these inputs are good, report back.  

Hi JR2, That's what I gather too. Do you know of the pins are numbered on the plug, or what's the numbering convention? Cheers Es  

Hi again, I hooked up a multimeter and checked a few things: Pin 2: Ground: OK Pin 5: Resume: 12V when pressed (car driving) Pin 7: Speed Signal: <1V AC or DC, no significant change with speed. Also checked if it's a variable resistance, doesn't seem so. Pin 12: Cancel. Permanent 12V, goes to 0V when pressed. Pin 14: Set:12V when pressed. I forgot to check the brake switch, which goes to Pin 12. I take that the speed signal is not present?! Am I right in thinking that the speedometer gets it speed signal from somewhere else? Cheers Es  

The_Nuge said: I take that the speed signal is not present?! Am I right in thinking that the speedometer gets its speed signal from somewhere else? Click to expand...

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I just checked the function of the brake switch on pin 12: when the brakes are applied, the 12V is also cut, like with the cancel switch. Re. the speed transducer, is it possible that the signal is a pulse of some kind, which is why an AC or DC signal isn't visible on a digital multimeter? Cheers Es  

I checked pin 7 again with the frequency function on the DMM, and I get a signal that varies roughly between 200 and 800Hz. It doesn't change 100% consistently though! Cheers Es  

Sorry but the weather did not co-operate today. I will try again tomorrow.  

Thanks! I'll see if I can test the speed signal at connection 30 with the car on a lift and running - easier than trying to run a secondary wire into the car I think. I took the original ECU out of its housing, and the PCB looks immaculate, which everything covered in lacquer. Is the speed signal generator also a GM part that can be hap cheap(ish)? Cheers Es  

It's me again 😉 Is there a way to test the actuator in the engine compartment, just to eliminate that as a cause? Also, is there anyone here in Germany who'd be willing to lend me their functioning ECU to check that that isn't the issue? I'd obviously "lend" that person a couple of good bottles of wine in return 😊 Cheers Es  

The_Nuge said: Is there a way to test the actuator in the engine compartment, just to eliminate that as a cause? Click to expand...

motorman said: Cruise Control dropping out It's relatively common to find both Senators and Carlton GSi's without working cruise control. There are two main failure points with the system. Under the bonnet the socket/plug on the actuator is a horrible design and not really suited to the oily under bonnet environment (especially as it carries a fair bit of current). So pull the connector off and give it a good clean and spray in some contact cleaner / lubricant afterwards! The other failure point is the control unit itself. This has been tracked down (not by me it must be said, an Autobahnstormer several years ago) t o faulty electrolytic capacitors which have probably fail due to drying out at high temperatures / long use. There is a 4.7uF which is used in the timing circuit which was believed to cause the units to 'kick' out of cruise after a while I replace these with a more robust tantalum capacitor. Others have suggested that all the electrolytic capacitors in the drive and input region be replaced. The other capacitors are connected with the interface to the actuator, as the lid is off you might as well change them all. The capacitors used are Philips 2222 030 38228 2u2 axial (numbers 1 and 2 in the photograph below), 2222 030 38109 10u axial (numbers 3 and 4), TAP 4u7 tantalum (number 5), and nichicon PM 10u radial (numbers 6 and 8). Click to expand...

Conformal coating is on the PCB. You cannot visually inspect a circuit board with the coating and it has to be removed. Only then can you visually inspect solder joints for defects under a magnifying glass. Defective solder joints are a leading cause of ECU failure.  

Hi Wraithman, You're right, but my experience repairing other electronic stuff tell me that these joint look OK. The other ECU I bought was supposed to be functioning, which is why I'm hesitant to send one of them off for repair before I've eliminated all other possibilities. Es  

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R107 500SL Cruise control actuator removal

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On my 560SL, the Cruise Control Actuator cord routes under the Windshield Washer reservoir, and then connects to a receptacle on the side of the Radiator Support. Unscrew the Windshield Washer reservoir and set it aside. Get yourself a good flash light and fondle the electrical cord from the Actuator to where it terminates on the side of the Radiator Support. It plugs in there.  

cwmoser said: On my 560SL, the Cruise Control Actuator cord routes under the Windshield Washer reservoir, and then connects to a receptacle on the side of the Radiator Support. Unscrew the Windshield Washer reservoir and set it aside. Get yourself a good flash light and fondle the electrical cord from the Actuator to where it terminates on the side of the Radiator Support. It plugs in there. Click to expand...

I managed to unplug the unit (the connector is clipped to the back of the front panel) and replace the actuator with one that apparently works. Still no working CC. Previously my local indie said they tested the control box, and swapped it with a known functioning unit which did not work either...so they suggested the actuator. Ho hum...what next to try?  

Worth a shot, but I've tried several spares (W126 actuators are identical, and more plentiful in JY's here), and have never seen one fail, even of of very high mileage (>250K mi) cars.  

Here is the wiring diagram for my 85, you could test the actuator by applying 12V across the motor and clutch briefly. Measure the potmeter resistance.  

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There is a thread on this forum showing how to test the Actuator by applying +12V to certain pins and observing if the internal motor moves.  

I went through this myself a couple of times on my '87 500 SL having convinced myself that the ECU was fine since I swapped it with a "working" one. Id agree with Strife2 the actuator doesn't seem to be the problem. Having read several threads on the ECU re-soldering fix, I did this myself - took about 2 hrs having stripped the varnish first. Still intermittent. Then I tried the same I the "new" "working" one. worked for a while then stopped. Then found a thread which said its not (just) the soldering but the electrolytic capacitors fail in the ECU and need to be replaced. The ECUs or the "fix services" seem to be a premium cost (£250) for the SL and I gave up - a bit beyond me and instead tried an ECU from a later merc (£25) - a '93 and it worked a treat straight away and been perfect since. It looks similar, different part number, blue plastic but same connectors. I just swapped over the coding plug.  

Mine became intermittant, resoldered about 200joints and replaced all the electrolytes, Has been working fine since. Yka used a nice trick, removed the card from the box, much easier than removing the box.  

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• Honda Accord Factory Facts
• 2000 Honda Accord Instructions

Crusie Control Actuator and Throttle Cable Adjustment

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Hi all, Before attempting to clean the throttle body of my 2000, I read in the Service Bulletin 01-004 (Throttle Body Cleaning), an instruction to adjust the cruise control and throttle cable after re-installing the throttle body. Would like to know the details before taking it apart. Does anyone has that instruction? Appreciate if you can share. It mentions page 4-55 of the 1998-01 Accord Service Manual for the cruise cable and page 11-32 for the throttle cable. Thanks!  

Its a little hard to describe without seeing the diagrams in the service manual but I'll try. The throttle cable is supposed to have 3/8" to 1/2" deflection in the cable when you push the spring loaded throttle body linkage (where the cable attaches) to remove the clearance. The cruise control cable adjustment is supposed to provide 0.150" inches of movement of the linkage on the throttle body (where the cable attaches) before the engine speed starts to increase. The 0.150" is measured at the top where the cable attaches. You can pull on the cable by hand with the engine idling to check this adjustment. Both of the cables adjust by means of the nuts on the end of the cables. Good Luck  

Thanks nehonda. It is easy as I removed the bracket that holds the cable, which is mounted on the engine. Also loosen the nuts at the bracket enables me to remove the cable around the "pulley" for both. No calibration required. The car is running much smoother after cleaning.  

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