2nd Gen Non-Engine/Transmission ABS & Brake light illuminated

[HEMI®Dart]

The ABS and Brake lights come on when backing-up pumping the brake pedal several times @ idle? Pedal gets "hard" also.

 

[GAmes]

I've read several threads about this problem. A lot of times it is the ABS sensor in the diff. Your truck also has a vacuum pressure switch in the system. I would check that first. It is mounted on the left front inner fender IIRC.

 

[HHhuntitall]

Yeah, the loss of vaccuum is what makes the pedal hard and causes the lights to come on. You're either over working the vaccuum accumulator, there is a leak, or at an idle, the vacuum pump can't keep up to the demand... . maybe all of the above.

 

[HEMI®Dart]

Low vacuum sensor on fender is new. I will try to find a leak. With engine off if I pump pedal could I hear a leak? The line coming off of the vacuum pump is 'soft'. The hose has DOT written on it w/ crimp clamps. Do I need to replace w/ both?

 

[HHhuntitall]

IT's possible for the line to close itself off if soft..... That would be cheaper and easier than a new vacuum booster, but I'm thinking that's what it is. If it's not leaking in the main lines, it's usually not a big enough leak to affect the booster. If you have a vacuum tester, try pulling vacuum on the booster and see how long it will hold vacuum. It should hold for several minutes, if not several hours. If it won't hold vacuum, the diaphram is worn out, and the booster will need to be replaced.