bhensarl

I've been trying to diagnose my non-functioning cruise control for some time now, with little to no success.
I've been using Adrian's book as a guide, and I've come to the function of the stalks on the steering column. I've never been able to get the cruise control to engage, and since I've already checked the fuse, brake pedal microswitch, and clutch pedal microswitch. When I press the stalk upward I simply get some resistance, but no audible click, or any click that I can feel. Is that normal?
Brian

jimq

sounds like mine. No click

Lorenfb

"I've already checked the fuse, brake pedal microswitch, and clutch pedal microswitch. When I press the stalk upward I simply get some resistance, but no audible click, or any click that I can feel. Is that normal?"

There are no relays nor mechanical devices in the cruise control unit (CCU) to cause a click.
Things to check:

1. speedo signal to CCU
2. actuator in engine compartment
3. brake/clutch inhibit switches
4. +12 on pins 1 & 3
5. +12 on pins 2, 4, 6 when lever is moved to various positions

springer3

Brian:

The control modules on German cars are notorious for cold solder joints. Pull the cover off the control module, and look at the solder joints, especially the heavy ones near the connector. It takes a trained eye to see the problem, because the solder will look fine. Any solder blob that is not uniformly glossy needs to be resoldered. Get the board under a microscope, or at least a good magnifying glass for the inspection. Look at all the components to see if any look like they overheated. The "rebuilders" have a racket, because most of the time they resolder a bad joint (zero cost), or replace a transistor (pennies). "Refurbished" control modules sell for half of retail - several hundred $$$ typically. Not bad for a few minutes work.

C24FUN

Brian,

When I bought my '90 C2 the cruise was non-functional. I went through some of the same troubleshooting that you are doing then I happened to look at the connection point behind the hot air blower in the engine compartment where the cruise wiring connects to the engine wiring harness. The connector was hanging loose! Obviously it had fallen off or more likely a mechanic had forgotten to re-connect it after some engine work.

Worth a look if you haven't already.

Good luck,

Jim Grant

Adrian

Dear Brian,
I would do as suggested by Jim to check the connectors but to expand your search to under the right seat.
I have seen and helped with this kind of problem a number of times and if it is not the micro switches then the problem has been the control unit connector.
Dry solder joints have been mentioned seen that before but most common by far is pulled or cut wiring.
Ciao,
Adrian.

darth

Car's in the shop and I havn't used the cruise control for a while but don't you push the stock forward rather than upward to engage?

Hope it's that simple!
Bill
90C2