I have a 1990 Chevy Blazer K5 350 4-wheel drive. I am having problems with my brake dash light coming on after reaching 35mph and staying on till I turn blazer off. I have changed the brake switch and the brake computer, but I am still having the same issue. My actual brake lights work fine. Just very annoyed that the dash light will not go off. Any suggestions??

 

on my 85 i replaced the rear brake lines (they were leaking) and the wheel cylinders and the light went off. not sure why but it worked and was cheep.

 

As Z71Guy said, replacing the wheel cylinders might fix your issue. Happened on my 1990 Blazer and the light went out after I replaced them.

 

From what I understand there are 2 conditions for the brake light on the dash to come on. First one being obvious, the parking brake has been engaged, second, there is a low pressure condition in the ABS system. Not sure what 35 mph has to with it, but if you do have ABS then I would say there is something going on with the pump/ABS unit. I would think if you are having an ABS issue the ABS dash light would be on. It's always possible there has been an ABS code generated but the dash bulb isn't working, burnt out. As for the parking brake, I just don't see it being the reason , unless something totally freaky is happening on the E-brake switch. But like you said that has been replaced.

 

have a k5 blazer and don't think they had a abs light. not leaking any fluid but will go and check wheel cylinders to see if they are bad

 

Doggpool,

Let us know what you find.