trouble shooting cruise control deactivation switch

[flacko93]

Been trying to trouble shoot my cruise control on my 93 F350. I fixed the problem on my 92 Ram (servo problem). I have a hunch it is the brake deactivation switch which I finally found. It was not on the master cylinder as the Ford parts department shows. It is further down on a brake line about 18" below the master cylinder. My question is: Is that switch normally open or normally closed? I checked continuity through the switch and it shows continuity (closed) when no brake pressure is applied. I then used a piece of wood to keep the brake pedal down (truck not running) and checked for continuity again, and I still had it! Thus the switch is closed with and without pressure on the pedal. That doesn't seem right. What do you guys think? [img]/ubbthreads/images/graemlins/shrug.gif[/img]

[cdnsarguy]

The normal deactivation is done by the BOO switch (brake on off) and brake light power, the deactivation switch is the final backup to that.

DESCRIPTION AND OPERATION for 93 Speed control

The speed control system is designed to automatically maintain vehicle speed at any driver-selected speed above approximately 30 mph and below approximately 125 mph. The system is comprised of an electronic servo which consists of a throttle actuator with integrated electronics and other parts including an actuator cable, horn relay, driver control switches, a brake lamp switch and a deactivator switch. The speed signal is generated by the Programmable Speedometer/Odometer Module (PSOM). The electronic servo is mounted in the engine compartment and is connected to the throttle linkage with an actuator cable.

PM me an email addy and I will send troubleshooting info.........as there are test at certain pin positions.