Cruise control

Ive read numerous threads about inoperable cruise control units on various models, however, my problem appears to be somewhat unique. When I turn the cruise on, there is a small orange indicator light on the wiper control arm. The light illuminates fine, so I have power. When I attempt to set it, however, and I release the set button, the system shuts off and the orange light goes out. I can also hear a small relay click up under the dash.

I actually got it to work the other day, for a whole 8 miles, then off, and couldnt recover it. I replaced the motor assembly and still the same problem. Im leaning toward the control unit, but I dont know where it is.

If anyone could help me Id appreciate it. I realize this car is older and probably very few people out there with any knowledge of the systems. Thanks alot.

i have a similar problem

I think you have the E30-series? i just checked my manual, think you have the a/t?

The cruise-control should be adjusted by under-pressure air (don´t know the english expression...), so there must be some hoses at the throttle-unit of the cruise-control. If you have there a vacuum-leak it won´t work.

Also there could be problem in the wiring of the control arm. normally there should be a green "cruise" light under the gear-indicator. If it flashes or doesn´t light the system doesn´t accept the setting.

Another possibility could be creep stress between the brake-switch and the chassis. then the system will think you´re breaking and shut down....

Best would be to unbuild the controlarm, check the wires and rerbuild it. Control all elektronik connections.

im not to worry about it. mostly a vaccum leak or the sending unit to switch use the curise control could of went wrong. its a 5 speed