2nd Gen Non-Engine/Transmission Brake light on

[wcjp]

About a month ago the brake light came on until shut down. Four days ago the brake light started blinking intermitently. I changed the fluid in the master cylinder about three months ago. I checked it recently. It's probably a loose wire. But, where?



Also, I don't know if this is related. Every few weeks, the brakes become very sensitive. Happens for about 10min and then back to normal.

 

[Blackcloud]

if the brake light is coming on "by itself",it sounds like the brake pedal switch under the dash is in need of adjustment or replacement. The touchy brakes... moisture/humidity sensitive pads???

 

[bighammer]

Brake light on the dash or back of the truck?

 

[wcjp]

The Dash

 

[B.G. Smith]

Brake light

May be one of the ABS sensors acting up. Remove the filler plug in th edifferential and see if it has metal particles on it. I had bearings going bad in mine and the metal particles were interfering with the sensor in the diff. causing the light to come on. bg

 

[bighammer]

the 2nd post faked me out and I thought it might be the real brake lights we were talking about. If there is a pressure difference (like air in a circuit) the light will come on. I would think the ABS sensor would turn on ABS light before brake light. Maybe check connections on the bias valve or check with the dealer.

 

[Paul Somers]

3 things

One of three things turn red brake light on. The one on dash.

1 Parking brake switch

2 pressure difference front and back hydraulics

3 CAB failure or CAB detected failure. Should also set ABS light so I would think its 1 or 2 is problem.

 

[bighammer]

I forgot about the parking brake



Another thing to add to the list is low vaccuum. I'm not certain, but I think I remember seeing a sensor to monitor vaccuum. I would guess if it's low, the light would come on.

 

[wcjp]

It was the parking brake signal. I found out it works off ground. The attachment was loose and bouncing off the chassis for the dash. Thanks.