quick question about relays

[bastianshaw]

Ive been trying to fgure out my abs problem which started after a jumpstart. My first thought was the relay but after changing it and opening my old one up there is no break in the line like a blown fuse, so it worls right? is that the fail point?

[jlevie]

Here is a quick guide to troubleshooting the ABS:

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 light goes out after engine start and only comes on 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.

[Hellabad]

Ive been trying to fgure out my abs problem which started after a jumpstart. My first thought was the relay but after changing it and opening my old one up there is no break in the line like a blown fuse, so it worls right? is that the fail point?

Are you sure you changed the correct relay?

I'm just asking because the blown relay is very, very, very common.

[StereoInstaller1]

I need to figure out how to "sticky" stuff, this thread needs to be re-titled, moved and stickied. This is good info here.

[jlevie]

I'd suggest a sticky FAQ for each sub forum. Then you can paste in things that should be saved.

[bastianshaw]

Are you sure you changed the correct relay?

I'm just asking because the blown relay is very, very, very common.

THis brings up another question, on bluntech there are numerous "abs" relays, I changed the one under the steering, arre there more and where are they located? I didnt see anything in the bentley?

[jlevie]

There is only one ABS really and it mounts just above the ABS module.

[bastianshaw]

There is only one ABS really and it mounts just above the ABS module.

Ok so back to my origional question. If the wire element in the center of the relay is unbroken, the relay is good right?

[bastianshaw]

no one cares

[StereoInstaller1]

Ok so back to my origional question. If the wire element in the center of the relay is unbroken, the relay is good right?

You know, I highly recommend not using your eyeballs to test electrical circuits. I think you should browse the Bentley, see what you can find.

I know I would be using a testlight to test that relay while looking at the ETM, but all I have ever done with the ABS circuit is swap relays, they always work after that...honestly never done any diagnostics on one, just swapped the relay and been all good.

Eeeeeexcept for my daily driver, and I don't mind not having ABS, the brakes are still great, I can modulate, too busy, DGAF, the usual cobblers shoe story.

Go find your wiring diagrams, see if they make sense.

GL!
Luke