(!)(P)BRAKE light staying on all the time.

[8thNote]

I have a '94 C1500 extended cab/short bed with 5.7L auto. My parking brake light is illuminated any time the truck is on. It just started doing this a couple of days ago. The p-brake works great and it fully disengages when I pull the release handle. I used to own a '04 Ford Crown Vic that would illuminate the p-brake light if the brake fluid resevoir was low, but mine is not low. Any one have any suggestions as to what may be causing this? Its a minor thing, but irritating none the less. Thanks in advance.

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[Schurkey]

Why is this in "Engine Performance"?

Three things cause the light to come on.
1. Park brake cable gets stiff/high friction, so the park brake pedal does not FULLY return. Lift up on the park brake pedal, see if the light goes out. This is probably the most-common; at least both of my GMT400s suffer from this. As a result, I don't use the park brake like I should, which then meant that the rear brakes of my K1500 wouldn't properly adjust. A cascade of failures stemming from two root causes: Crappy park brake cables, and crappy rear brake design. I still have the crappy cables, but I scrapped the light-duty rear axle with the light-duty brakes.

2. "Safety switch" in the combination valve is off-center, indicating a failure in either front or rear hydraulic system. GENERALLY, this results in a brake warning light that's "on" when you step on the brakes, but goes off when your foot comes off the brake pedal. Verification of proper braking is essential. You could remove the wire from the safety switch, and see if the light goes out.

3. Wiring fault in the two systems above; some of the wire harness has grounded on a stray bit of metal structure. You'd expect the light to blink as the harness jiggled over bumps.

 

[MSCustoms]

Check for an abs code. You have to use a paper clip in the obd port to have it flash like the check engine light. It is a different pin then the one used for the engine code

 

[7Brandon07]

I had a car once that had a sensor on the parking brake lever much like the sensor for the brake pedal don’t know if these trucks are like that probably not.

 

[dmhscorpion]

My Tahoe had this issue. I found a short in the 7 pin Bargman trailer wiring socket.
dmh

 

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Try pulling up on the p brake pedal after releasing it. Mine did this and had to readjust p brake pedal to fully turn off light

 

[8thNote]

Try pulling up on the p brake pedal after releasing it. Mine did this and had to readjust p brake pedal to fully turn off light

I have tried this. The parking brake pedal is all the way up when released, it does not move at all when I try to lift it.

 

[8thNote]

Ok, I finally checked the code. When I bridged slot A and slot H on the ALDL, the (!)(P)BRAKE light started flashing. 1 long flash followed by 4 short flashes, which means it is code 5 (5: Excessive Actuations of the Dump Valve). I unplugged the harnesses going to the dump valve and the proportioning valve, and disconnected the positive battery terminal. I then plugged the harnesses back in and reconnected the battery terminal. The light went off, and so far has stayed off.

Thanks to everyone for all the tips and suggestions.