What causes the BRAKE light to come on?? (the bad one)

[XHitman396]

So the brake light under the fuel gauge, the one that means something is wrong, comes on when i mash the brakes while the truck's in drive. i just swapped in a 14bff and re-did the brakes, we bled them then adjusted them, but they still dont work extremely well, and the light only comes on when i slam them on, and when it's in drive, doesnt do it in park. any ideas? what exactly sends the signal to the light? sensors? where? any ideas would be appreciated... thanks..

 

[sebban]

I had the same after my swap. Just keep bleeding the brakes, I suspect that there's still air in the system..

 

[loafer]

The brake light is activated by a pressure differential switch on the combination valve. It comes on when there is a difference in pressure between the front circuit and rear circuit. It's very sensitive and usually means there is a small leak in the system or you still have air somewhere. Make sure your there is no trapped air in the MC or combo valve too.

I've never done a rear disk swap, so I don't know how the combo valve behaves with disks. Others here will know this.

So the brake light under the fuel gauge, the one that means something is wrong, comes on when i mash the brakes while the truck's in drive. i just swapped in a 14bff and re-did the brakes, we bled them then adjusted them, but they still dont work extremely well, and the light only comes on when i slam them on, and when it's in drive, doesnt do it in park. any ideas? what exactly sends the signal to the light? sensors? where? any ideas would be appreciated... thanks..

 

[XHitman396]

hmm.. odd.. well the brakes are still drums, just new shoes/cylinders. i swapped the 14bff into my blazer, that's what i meant, sorry for the confusion.. well hell i guess ill bleed them a little more, or adjust them a little more solidly..

 

[loafer]

My bad. For some reason I thought you were doing a disk conversion with the 14bff swap.

Did the MC run dry when you swapped axles? If so, the easiest way to bench bleed it is disconnect the brake lines at the MC, screw plugs in, and pump the pedal with a 1-2in stroke until it gets real hard, then re-bleed the rest of the system.

hmm.. odd.. well the brakes are still drums, just new shoes/cylinders. i swapped the 14bff into my blazer, that's what i meant, sorry for the confusion.. well hell i guess ill bleed them a little more, or adjust them a little more solidly..