Cruise control module(126) circuit board
 

1984 300SD
Cruise control works in all functions, except when the unit is turned off by hitting the brakes, you cannot reset it until the key has been cycled off/on (interesting while moving). It will reset if you use the "off" position of the stalk switch to disengage. A substituted unit works perfectly (all other parts of the cruise control system check to spec. also). I have checked the printed circuit board for open or burned traces, and have resoldered several of the solder joints.

I know pin #8 is ground circuit and have tried to trace it, but I am too ignorant electronically to figure what components on the PCB would be at fault. Does the reset circuit rely primarily on capacitors to "recharge"? Do any of you EE types or E-techs have a suggestion? Thanks.

Bruce

It could be any number of things. The parts used on that module are all off the shelf stuff. So repairing it should be no problem once you can identify the defective part. But doing that is the real challenge.