Cruise control acting funky? Clean up the contact board!

[billb]

My cruise has been misbehaving a little. In 10 minutes this morning (before work), I field-stripped it and I think helped it out. 10mm socket, 8mm socket, and a standard-blade screwdriver, some WD-40 and a paper towel.

Remove connector from cruise unit.
Remove cruise unit bracket from car using 10mm socket/ratchet.
Remove bracket from cruise module using 8mm socket/ratchet.
Remove 7 screws from housing. Pop plastic solder point and remove housing cover. Remove clock spring and main gear stop. Rotate main gear counterclockwise while pulling it off main shaft. You will see two tracks that the wiper arms run on. Using either contact cleaner or WD-40, clean the tracks, then wipe clean with paper towel. Reinstall main gear, winding clockwise to take up slack in end of cruse cable. Reinstall main gear stop. Reinstall clock spring, giving one full turn to provide tension. Verify that gear rotates freely clockwise and pulls throttle valve open during this rotation. Reinstall cover and 7 screws. Reattach unit to bracket. Reattach bracket to car. Reconnect connector. Drive.

[billb]

Day 2 of working great. Think that did the trick!

[shogun]

WD-40 is not that good for this application.

stabilant 22A Electrical Contact Enhancer

Model: All BMW
Complaint:
Connectors which carry low current are more likely to form deposits which affect the resistance of the circuit through the plug connector. Depending upon the particular circuit these deposits can cause malfunctions and consequently activate warning lamps and check control indicators.
Remedy:
Part replacement can temporarily stop the problem.
If the connector is the problem then without disconnecting the connector measure the resistance of the circuit running through the connector to make sure the connector has a high resistance. A good resistor will have close to 0 ohms resistance.
Visually examine the male and female terminals in the connector housing by removing them. Look at the integrity of the wire crimps, and in some male terminals the integrity of the weld of the male pin to the terminal. Then reinstall.
With a zero residue electrical contact cleaner liberally spray the male and female connectors, and allow the air to dry.
Apply Stabilant 22A to both male and female terminals so they are saturated, and reconnect the connectors while they are still wet. When the Stabilant 22A dries it will leave a thin coating of polymer film which is conductive between mating surfaces, and is non-conductive between adjacent pins. It can also prevent the formation of more harmful deposits.

[billb]

If I had stabilant, I would use it. But I had WD-40. Used it primarily to act as solvent (would've preferred a contact cleaner), but didn't have that either. But, as it took a total of 10 minutes start to finish, if I have to go in there again, no big deal.

But thanks for the suggestion. Hopefully if someone else goes in there, they'll have Stabilant or something comparable.

[genphreak]

BillB, Shogun, thanks for sharing. Was there no grease in there when u opened it up? They seem to love to use that on some 'contact arm' wiper applications, I think it is a special grease in these cases though (E.g. shifter switch)- some type of electro-concductuve grease... probably there are several.

[pundit]

My cruise control has been playing up too.
It intermittently drops in and out.
It remembers the last set speed so it's not a memory issue.
It more like a loss of power to the CC motor so I'll check those contacts - Thanks

[shogun]

pundit, if the speed sensor on the final drive is dirty or not functioning and not giving a good signal, and if the wheel sensors do not give a clear signal, then you also have such a problem as described. Cruise control needs very accurate signals, if not, for safety reasons it will switch off.

[Arxon]

My cruise has been misbehaving a little. In 10 minutes this morning (before work), I field-stripped it and I think helped it out. 10mm socket, 8mm socket, and a standard-blade screwdriver, some WD-40 and a paper towel.

Remove connector from cruise unit.
Remove cruise unit bracket from car using 10mm socket/ratchet.
Remove bracket from cruise module using 8mm socket/ratchet.
Remove 7 screws from housing. Pop plastic solder point and remove housing cover. Remove clock spring and main gear stop. Rotate main gear counterclockwise while pulling it off main shaft. You will see two tracks that the wiper arms run on. Using either contact cleaner or WD-40, clean the tracks, then wipe clean with paper towel. Reinstall main gear, winding clockwise to take up slack in end of cruse cable. Reinstall main gear stop. Reinstall clock spring, giving one full turn to provide tension. Verify that gear rotates freely clockwise and pulls throttle valve open during this rotation. Reinstall cover and 7 screws. Reattach unit to bracket. Reattach bracket to car. Reconnect connector. Drive.


nice description, but, how do you remove clock spring? Ido not want to think of releasing the spring...

[Arxon]

Finally, I opened the unit, (didn't take out the clock spring), I used WD40 but nothing happened, still not working

[Jehu]

Reviving this thread as yesterday my cruise control wouldn't let me disengage it..

day before it suddenly wouldn't engage at all.

The next day it engaged but wouldn't shut off and actually started accelerating.

I had this happen before on another 540 and completely forget how I addressed the issue.. I think it just self corrected because I never opened or replaced the unit

I also seem to recall there was possibly an issue raised regarding the switch in the steering column stalk which could be repaired.

I have read about the toothed wheel losing teeth and failing to engage but the auto-acceleration and failure to deactivate is much more of a problem .

For the time being I will be simply unplugging the harness connector until I get a chance to open the unit as described.