Brake Light On Dash Stays On

[mdwatson]

What causes the brake light on the dash to stay on other than the obvious emergency brake engaged? It's a 86 2.5L with new master cylinder, booster, calipers and rear cylinder. It still has the rear valve but I'm not sure if it works, it has no rod on it.

[87MJTIM]

There is a plastic clip with a copper tabs connected to the park brake.  When the brake is pushed down, the copper tabs separate causing the electic contact to flow to the idiot light.  When the brake is off (up) the copper tabs ground out and the light is off.

 

Check the park brake for the plastic part.  Mine is light blue.  Make sure the power wire is connected.  Clean between the copper tabs.  Grease can get on them and weaken the contacts.

 

If that doesn't fix it, you can try three other methods:

 

1. cover the light with elctrical tape.

2. remove the offending light from the dash

3. or wait for the bulb to burn out.  ;)

[nitroxsteve]

Low oil in master cylinder will do it too.

[mdwatson]

The fluid level is good and I'll check the connections at the e-brake. Didn't know if there was anything else to look for that could cause it to come on.

[nitroxsteve]

There should be a pressure switch below the master cylinder. I would check that too.

[95wrangler]

I have the same problem.I found that after starting the engine just turn the key back mabe 1/8 in. The lite goes off.

[HOrnbrod]

Dash brake warning light causes:

1. parking brakes are applied
2. very low pedal
3. low fluid level
4. excessively worn brake lining
5. there's a pressure differential between the front/rear hydraulic systems

[Eagle]

If the rear circuit wasn't bled properly and the rear height sensing valve is till in place, it is likely that the rear circuit has air in it and that would be enough to trip the warning light.

[mdwatson]

You might be on to something Eagle, I've never had a solid brake pedal on this truck. I have recently re-bled the brakes and the light came on about a week later. How do you properly bleed the rear brakes with the height sensing valve? Also how do you check the pressure differential switch? I looked at it and the wires are plugged in.

[skidoo_j]

http://comancheclub.com/topic/40428-brake-bleeding/

[mdwatson]

Thank you skidoo_j