Cruise Control Doesn't Disengage

[scottb]

I have an 84 Carrera. The cruise control engages properly, holds speed, but does not disengage when I hit the brake pedal or clutch pedal. Any thoughts on what's going on? Help would be greatly appreciated.

[Ilan]

Check to see if your brake lights are coming on when you're depressing the brake pedal. If not, it means you have a bad brake switch, which is why cruise won't disengage. (been there done that). A new brake switch is inexpensive, but to install it, you need to bleed the brakes.

[lukeh]

What Ilan said. Same thing happened to me. Brake lights also didn't work. The first time the cruise didn't turn off it gave me quite a scare. It felt good to know that I could react under pressure.

[scottb]

I'm reviving this thread because the problem persists. My mechanic adjusted the switches, but the cruise control still doesn't disengage when I hit the brake or clutch pedals. Any thoughts on what might be the problem would be greatly appreciated.

Thanks, all.

[Thomas Owen]

You can check the wiring at the cruise brain under that dash. Your 2 switches may be good, just a problem in the brain circuit.
Pin 6 on the harness will have +12vdc when brake is pressed.
Pin 12 is a ground that will be provided to the cruise relay in the trunk when the clutch is pressed.
There is a possibility that someone bypassed the switches because they could not diagnose a problem (maybe 1 of the switches is bad so they eliminated them both).
Let me know if you have further wiring questions.

[scottb]

Where is the unit under the dash, and what does it look like?

Thanks, Thomas.

[Thomas Owen]

The cruise brain is a small silver box about 4" x 5" x 1.5". It is under the dash just below and maybe slightly to the right of the radio. It will have a large wiring connector plugged on from the passenger side. There may be a black cap snapped over the wire harness holding it onto the box - just pry it off and you can then unplug the wire harness.
Good luck-