Cruise Control & Brake Dilemma
Re: 1987 560 SL
The cruise functions normally at all functions when operated by the control lever on the steering column. As soon as you touch the brakes with cruise engaged, the unit is somehow "reset" and becomes inoperative until the car (ignition) is turned off and restarted, at which time the cruise is functional again until...
I was advised that the brake lights can be voltage culprits causing some flucuation that triggers a problem such as this. I switched brake and back up light bulbs (as the latter filaments looked to be brand new in comparison) with no success. The concept of some electrical gremlin in the brake circuit makes sense based on the pattern of failure, however. Any other suggestions for the next step in troubleshooting?