Brake light in dash stays on

I have a 96 blazer LT. Today when it snowed here my son said it wasnt engaging the 4wd. He determined this by setting the parking brake and giving it gas to see if the front wheels would make it move (Yes I think he does use his brain on occasion, but not this time) during which it made a popping noise in the rear. After researching the threads I was able to find and repair the loose vacuum hose under the battery. Now the 4wd is working but the brake light in the dash stays on. I set and released the parking brake (hoping the switch was stuck) and the daytime running lights indicator goes on and off as it is supposed with the parking brake. The anti lock brakes are working and all lights are working. Any ideas? Thank you, Rob

Red or yellow?
Does it get brighter when emg brake is down?
Is the master cylinder full of fluid?
MT

Thanks MT!! The indicator light is red and does not change brightness. Didn't think to check master cylinder fluid level as it was serviced 1,500 miles ago, the front 1/2 master cylinder was empty and I filled it. What would cause the drop in fluid level? I know I need to bleed the brakes now, but I have good pedal. Light is still on. Will air in line cause indicator light to stay on or is it something else? Thank you for your help, Rob

I have the same problem...I got stuck and used the parking brake to get both wheels spinning...problem is it never went off. Topped off master cylinder to rule that out. Still on.

The light is just as bright with the brake on or off.


97 GMC Jimmy

Thanks MT!! The indicator light is red and does not change brightness. Didn't think to check master cylinder fluid level as it was serviced 1,500 miles ago, the front 1/2 master cylinder was empty and I filled it. What would cause the drop in fluid level? I know I need to bleed the brakes now, but I have good pedal. Light is still on. Will air in line cause indicator light to stay on or is it something else? Thank you for your help, Rob


You have a leak someplace.
Does it still have a full pedal?
Unplug combination valve switch to see if it is turning on light.
If front or rear brakes do not hold pressure or have a leak the combination valve will shut off that end and turn on light.
Does the front tank feed rear brakes on that one?
If so check all rear brake lines and wheel cylinders.
If it feeds the front brakes check front calipers and brake hoses and lines for leakage.
If valve has tripped you may have to bleed brakes front and rear to center it back up or push the little plunger on it back in by hand sometimes recenters it.
and then check for leaks.
If valve is tripped it will not leak on the end it has shut off.

Good Luck MT