Brake lights on the dash

[Fred_M1010]

My brake light on the dash is on constantly.
It has happened now and then earlier, but now it's on all the time...
It gets brighter when I apply the E-brake, so I don't think the E-brake switch is the problem.
What more can cause this?

[ellis93]

The proportioning valve can stick to one side and can turn the light on. Simple to test, just un plug it. If the light goes off then that's it. Usually that means there is a wheel cylinder leak and that let the valve run to far out and caused it to stick.
Can be abs related, if your truck has it, but should have the abs light on as well.

[Richie O]

Also a low vacuum or messed up vac switch would cause it too.

[Fred_M1010]

Ok, I've tried disconnecting both prop valve and vac switch now, but it's still on.
Is there supposed to be an ABS light as well in the dash?
If so I'm probably missing the bulb for it...
So I'm guessing it could be ABS related.

[ellis93]

Drop the glove box and unplug the ABS module. It would be on top the a/c and black in color.

[Fred_M1010]

Thanks, I'll try that.

[Fred_M1010]

I tried unplugging the ABS unit, and the light went out
Then I reconnected it, and it's still out...
I guess it needed a reset or something...

But I do think I've got a leak somewhere as well, cause the pedal sinks slowly to the bottom when I apply the brake.
I can't see any leaks so I guess it's a rear wheel cylinder that's leaking....

When I think about it, it was a little wet when I changed the rear brake shoes a while ago,
but I thought it looked more like bad axle seals, so I just replaced those