D1 cruise not working

_ExpeditionMan

Well-known member
Dec 11, 2017
295
34
Texas
If your vacuum pump works, all the hoses in the engine bay are good, and you get a light from the switch you still have a few options.

1) check the brake switch on a bracket pointed at the brake pedal. It should have a vacuum line from through the firewall attached. The switch should also be making contact with your brake pedal when not depressed. If the switch is not fully depressed when the pedal is in the home position you will not be able to use cruise.

2) break out the multimeter and determine if your cruise control buttons are actually working

3) wire up a D2 or P38 cruise control module to replace the constantly failing D1 modules.
 
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discostew

Well-known member
Sep 14, 2010
7,706
1,015
Northern Illinois
Wire up a D2 module is probably your best option. There's a write up around here someplace. The vacuum lines do get cracked and leak going into the brake switch. But like was mentioned earlier, if your vacuum pump runs and the system holds vacuum on the hose going to the brake switch then I would suspect the module. Open up the case on your old one and look at two drivers in it. One runs the pump and the other closes a vent. One will probably be noticeably burnt.
 
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pnkelly1

Well-known member
Jan 10, 2019
131
21
richmond, va. 23221
If you vacuum pump works, all the hoses in the engine bay are good, and you get a light from the switch you still have a few options.

1) check the brake switch on a bracket pointed at the brake pedal. It should have a vacuum line from through the firewall attached. The switch should also be making contact with your brake pedal when not depressed. If the switch is not fully depressed when the pedal is in the home position you will not be able to use cruise.

2) break out the multimeter and determine if your cruise control buttons are actually working

3) wire up a D2 or P38 cruise control module to replace the constantly failing D1 modules.
Cheers, vacuum line on brake switch, will check brake pedal contact and cruise buttons this even!