OK, Seriously WTF

[bastianshaw]

So im still trying to figure this out w/o going to a shop.
ABS and cruise control non op

1. ABS relay is good.
2. brake and clutch switches are good.
3. MY BRAKE LIGHTS WENT OUT(blown fuse 6)<----- Bentley says that the control module for the CC gets ground through the brake lights, WHERE? if my fuse blew doesnt that indicate a short? I pulled the rear trunk panel and inspected the wiring and it looks good, I did find this:



It appears to be a killer fuse of some kind, the wire is not blown.
Regarding the CC i disconnected the rear sensor wires under the seat individually then drove, they look like this:
ABS light still on, I know I need to check the front ones, but im hoping someone sees this and has gone through this before.

[LJ851]

Thats not a fuse, it's a light bulb.

[bastianshaw]

Thats not a fuse, it's a light bulb.

im retarded. thanks for that, now then any ideas on the ABS or CC?

[jlevie]

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.

[bastianshaw]

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.

Dude thanks for your reply but I've seen this a dozen times now, copy and pasting this every time a ABS question comes up doesn't help ppl that have already done an extensive search.

[LJ851]

Uuumm.... He just told you how to find your problem, how is that not helpful?

[bastianshaw]

Uuumm.... He just told you how to find your problem, how is that not helpful?

Narrowed it down to a wiring problem, module or relay...WOW killer thanks.
I dont want to seem un gratefull I welcome the post its just that ive seen that already and it hasnt helped, like I said, Im looking for someone that had this same problem, these cars tend to break the same, ABS relay, odo gears, SI lights ect ect. I think thats why we post and ask for help here, we are all having the same problems. Right?

[LJ851]

No. If that post didn't help then you didn't do what it said.

If you are waiting for someone to randomly tell you what to do and guess it right then you will just have to wait.

If you want to fix your car follow those guidelines.

[Kingb]

No. If that post didn't help then you didn't do what it said.

If you are waiting for someone to randomly tell you what to do and guess it right then you will just have to wait.

If you want to fix your car follow those guidelines.

ganz genau. Sind Sie behindern??

[burkey001]

The response from Jlevie looks pretty much as detailed as you could want.
One could suggest that if you are unable to distinguish between a light bulb and a fuse then maybe you shouldn't be wasting your time troubleshooting this issue as you have bigger fish to fry.

[lbreevesii]

Sorry to threadjack a little, but i've got a question.

My fault lies in the last category, it only comes on while moving. however, so far it has ONLY come on while cruising at highway speed, never around town, on back roads, etc. Does that help narrow it down at all? I still plan on doing the test with unhooking the sensors, but i'm just curious.

[jlevie]

Sorry to threadjack a little, but i've got a question.

My fault lies in the last category, it only comes on while moving. however, so far it has ONLY come on while cruising at highway speed, never around town, on back roads, etc. Does that help narrow it down at all? I still plan on doing the test with unhooking the sensors, but i'm just curious.

That could be a wheel speed sensor problem, or it could be a bad ABS module. Generally, if a wheel speed sensor is bad the light will come on shortly after the car starts moving.

[bastianshaw]

ok ive now tried replacing the ABS computer w a known good one, and traced the wiring from the right rar taillight through the trunk to the rear seat....ABS light still comes on and STAYS on ruling out a sensor right, any ideas?

[bastianshaw]

so it appears I have a wiring problem right?

[jlevie]

ok ive now tried replacing the ABS computer w a known good one, and traced the wiring from the right rar taillight through the trunk to the rear seat....ABS light still comes on and STAYS on ruling out a sensor right, any ideas?

If the ABS relay is good, replace the ABS unit. The relay, ABS module, or ABS unit can cause the light to come on with ignition and stay on.