73 Park Brake Switch

[Carlton Huitt]

My park brake light on the lower left of the instrument cluster is steady on. Does anyone know where the switch is so I can repair? Is it park brake warning or main brakes? Oh boy....

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[75gmck25]

Is that the original instrument cluster? My '74/'75 cluster has the amp guage and mechanical oil pressure gauge, but the brake light is embedded in the fuel gauge. Most early clusters I have seen also did not have numbers on the temp gauge.

I do not have a park brake switch on the pedal, so the brake light is connected only to the proportioning valve near the radiator support. If that brake light is on it means there is a pressure imbalance in the braking system (usually due to a leak), and the proportioning valve has popped to one side.

Bruce

 

[Snoots]

That light is in parallel with the Parking Brake and the Proportioning Valve.

If there is a problem with the Proportioning Valve that light is on.
If your parking brake is depressed or the switch located on the parking brake pedal assembly is out of adjustment that light is on.

 

[Carlton Huitt]

I’m not sure if it is the original cluster. I got the truck used multiple users. Thanks for the lead on the proportioning valve. I will start there and update the outcome here. Again I really do appreciate you taking the time to reply.

 

[73c20jim]

Same problem. It's on even if the truck is turned off.

 

[Carlton Huitt]

Stolll haven’t gotten it wired.

 

[Memaloose]

I too have a brake lamp in the fuel gauge on my '75. I noticed I don't have a parking brake light switch and wondered what it was for. I guess now, that it was installed specifically for a faulty braking system, that was thoughtful of GM.