ABS questions

[yeagers_e30]

I drive a '88 Vert and my ABS light is on. I have checked everything and found that the relay above the ABS brain was blown. So I resoldered it back and put it back in, started the car the light was still on, so I gave it alittle ga to raise the rpm and the light went out. Thats good news right...so I drive 20ft and pop the relay is bad again and the light is back on. this happened 3 times. Any help would be appreciated.

[jlevie]

The ABS light comes on when you turn on the ignition and goes out when the system voltage rises. The need to rev the engine might indicate that your alternator isn't working quite right.

Troubleshooting the ABS system isn't very difficult. It is a stand alone
system that only gets input data from the brake light switch, wheel sensors and
system power. The parts of the system are the ABS module located next to the
steering column, the ABS relay mounted above the ABS module, the ABS unit in
the left front of the engine bay, and a wheel speed sensor at each wheel.

If the ABS light comes on with ignition, but doesn't go out when the engine
starts, a wiring problem, bad module, or bad ABS relay are the likely
candidates. A failed or weak alternator will also cause this because the
system voltage won't rise enough. There is a fusible link inside the ABS relay
that can be blown. The relay can be repaired, or better yet replaced.

If the ABS light comes on when you turn on the ignition, goes out when the
engine starts, and then comes back on before the car is moving the cause could
be a bad module, a bad ABS unit, or a wiring fault.

If the goes out after engine start and only comes one when the car is moving,
there's a problem with one (or more) of the sensors. The simple test to find
out which sensor(s) is the cause is to disconnect all but one of the sensors
and drive the car. If the light comes on, that sensor is sending a speed
signal to the ABS and is good. Repeat with each other sensor to find the
one(s) that don't cause the light to come on. Since the ABS module has no
speed input besides the wheel sensors, if only a bad sensor is connected the
module can't tell the car is moving and thus doesn't fault on missing speed
signals from the other wheels. Once a bad speed sensor is found, if a new
sensor still doesn't work, there could be a wiring fault in that circuit or a
bad input channel in the ABS unit.

[yeagers_e30]

but I have checked everything and when i fix the the fuse on the relay and then start it and like i said i had to raise the rpms up alittle then it went out but when I moved it or let it sit after the light goes out the light came back on and looked at the relay and it was blown again.

[jlevie]

The light may be coming on because the fuse blew. And that is probably because the ABS module is drawing too much current. I'd swap in a known good ABS unit and a new relay and see if that works.

[yeagers_e30]

i would cept i have no spare parts for the brake system around and there are no locals with a e30 around here. and am low on cash due to a lay off.

[E30_fiend]

There are a lot of guys driving around with no abs. Learn how to do it then pull the bulb out of the cluster. Problem solved.


Taylor

[jlevie]

There was a time when no cars had ABS and one can live without it. But get into slippery conditions and ABS can make the difference between driving the car home and seeing the wreck on a flat bed.

I turn off ABS on my race car in the dry and only ocassionally get a minor flat spot on the tires. But I live by it in the wet.

[yeagers_e30]

i have been driving without it now for over two years now, but i do have a new edition to the family and it does make the difference between smack and phew in some tampa and orlando traffic

[yeagers_e30]

pulled all the sensors out of the car and the fronts look fine, but the rears look like they were mangeld and dropped, but the rings look good no damage. So no im looking for rear sensors for replacement.