Hi guys, I'm new to the forum posted in the newbie section first. Now to the dirty. I've got a 77 cutlass with what i think is a electrical issue. I know from the other posts this only comes on for two reasons. brake pressure is off on front or back or the parking brake is on or not fully disengaged. I don't have a parking brake was taken out years ago. Light did not come on until about a month ago now. Car has new front brake hoses, reman calipers up front, New cpp proportioning valve and i did get the little orange plastic tool that goes where the switch mounts to keep the valve centered. Here is the kicker the light goes off when i pull the parking light/ headlight switch on. It will go off if the car sits overnight then come back on when the car runs for 5-10 minutes. The plug in the first picture will turn off the light if I disconnect them. Also it will not turn off if I un hook it from the switch in the proportioning valve. Please help I'm losing sleep over this. Sorry for the long post just didn't want to leave anything out. brake pedal is more firm than it has been in a long time. Thanks for any help you can provide will be greatly appreciated.

 

Sorry, what ‘plug’ are you referencing in the picture?

 

Yeah, a bare parking brake pedal with no cables and spring tension may move around enough to depress the switch plunger.

 

The two wires to the left of the brake. It has the white connector on the top

 

The parking brake pedal assembly is completely gone from the car. The car has a rear disc conversion that was done last year. No brake pressure switch light came on then.

 

So where is the parking brake switch and wiring harness?

 

now that you mention it all the wiring should be still there. I don't remember cutting any wires. Wouldn't the light had come on back when I first took the pedal assembly out if the wiring was cut? That will be the first thing I will look at tomorrow thank you for the response. Would anyone on here happen to have a picture of the brake assembly still in a 76 or 77 cutlass? Or a car that would be set up the same.

 

Normally the only time that light comes on is if the switch on the combo valve or the parking brake switch supplies a ground to the light. Since it does not go out on when you disconnected the combo valve, thats not it. That leaves the parking brake switch or a stray ground short within the circuit. I don't know why it would go out with the headlight switch other than a backfeed somewhere.

 

what's the chance that my headlight switch is the cause? My interior lights also seem to be acting strange. If I pull the headlight switch once to turn on the parking lights the interior lights come on or were. Now they stopped working again. When I open the doors my 1/4 window lights are not working

 

I prefer to trouble shoot instead of throwing parts at the problem. Get the manuals for your car and follow the schematic. Courtesy and dome lights do run through the headlight switch but it supplies the ground side to complete the circuits.

 

Ok thanks for the advice looks like I got some searching to do.