Weird brake warning light problem

[Frank Enstein]

My brake warning light comes on after 1/2 to 3/4 mile after startup. Will not come on until I drive. Start and idle all day and not come on. Stops fine. Parking brake works fine. Both switches disconnected.

I had the dash out and cleaned up the wiring mess behind it. I think I misconnected a wire or the wire is rubbed through.

What I don't understand is why it only comes on after 1/2 to 3/4 mile. What did I tap into?

 

[SUBURBAN5]

My brake warning light comes on after 1/2 to 3/4 mile after startup. Will not come on until I drive. Start and idle all day and not come on. Stops fine. Parking brake works fine. Both switches disconnected.

I had the dash out and cleaned up the wiring mess behind it. I think I misconnected a wire or the wire is rubbed through.

What I don't understand is why it only comes on after 1/2 to 3/4 mile. What did I tap into?

That's a tough one. So if you drive around it comes on. What turns it off?

 

[AK49BWL]

My brake warning light comes on after 1/2 to 3/4 mile after startup. Will not come on until I drive. Start and idle all day and not come on. Stops fine. Parking brake works fine. Both switches disconnected.

What two switches?

Check your brake fluid level? What year truck? ABS may have a problem too, ABS light on?

 

[Frank Enstein]

The only thing that turns it off is the ignition key.

I disconnected the parking brake switch and the switch on the proportioning valve. Most of the ABS stuff is gone and I don't think this truck had it anyway. The truck is a Frankenstein of at least 9 vehicles. Stops very well though!
I just want the parking brake reminder to work correctly. When the pedal hits the floor when I try to stop I don't need to be told that the brakes don't work with a little light!

 

[AK49BWL]

Well if it's like that... If you have a 96+, just pull the diode out of the fuse block under the hood.

 

[Frank Enstein]

It's a 92 Mostly. It is supposed to be a 1992 K3500 CCLB
with a 454. It currently has a 350? with a carburetor.

 

[Frank Enstein]

New strangeness! On a 1+ hour ride the silly light started blinking almost randomly and it wasn't in time with the music. Also the lights in the upper left of the instrument panel sometimes don't work. Take out and clean the contacts?

 

[Erik the Awful]

...but have you checked your brake fluid level?

 

[Frank Enstein]

Yes. It's full and clean. I think it might be an ABS warning. There are no sensors or reluctors in front. I did repair a few wires that were cut when I had the dash out. I wonder if I reconnected the ABS warning?

 

[Frank Enstein]

Fixed! Unplugged the ABS box. Threw ABS stuff in the scrap pile and re-bled the brakes. Now to reconnect the parking brake switch so when I have a brain cramp it will yell at me to release the dumb thing before I need new brake shoes!