Truck info: '97 1500 5.2 4x4 auto, no ABS.

Problem: When I turn my cruise on the light comes on for about 10 seconds then the light goes off and it will not let me turn the cruise back on until I kill the engine and restart. It does this if the truck is moving or not. When moving I can try to set the cruise (during the 10 or so seconds that the light is on) and it will not set.

I checked the connector and vacuum hose and they are ok.

Searching on this and other forums have lead me to a speed sensor but I need verification on that before throwing $$$ at the problem.

Please help ASAP! 8+ hour drive on Friday!!!

 

Check your brake switch. There's an issue with them that hitting a bump wiggles the brake pedal enough that it trips the switch, thus canceling the cruise control. My guess is that if the switch is bad, the interruption is enough to prevent it from disengaging.

 

Well that would not let the system set but would it power down the cruise? (Light off = cruise off)

 

Yes. A faulty brake switch would interfere with the ability of the cruise control system to operate properly.

 

Interesting. I'll check it out. Any wiring diagram to this switch terminals?

 

I think you are right.

I went out and started the truck, turned the cruise on and waited... it shut off in about 10 - 20 seconds.

Shut the truck down then restarted, held the brake pedal in, turned the cruise on, smoked a cigarette, and the cruise was still on... released the brake and in 10 - 20 seconds it shut off...

Going to go get a brake switch.

Thanks for your help and I'll post back after changing it.

 

Well that didn't work. Any other suggestions?

 

UPDATE:

Cruise light stays on now. Will not set.

Good Vacuum at the 90 elbow that attaches to the actuator.

Scratching my head....

 

There is a DIY here on how to clean the switch, you might try doing that.

 

Just did that... didn't help.

Have power through the brake switch out to the servo.

Good vacuum.

What's missing? On another forum someone said to change the output speed sensor on the transmission. I hate to throw money at problems so what is your opinion on that?