ABS light on - E30 gurus please help! - PROBLEM SOLVED

[derber38]

To all E30 gurus out there…

I have an ABS light that will simply not turn off. Light is on after turning on ignition and remains on while driving.

I have tried…

• Replaced both ABS relays from E30 with known working ABS relays.
• Replaced ABS computer module from E30 with known working ABS computer module.
• Confirmed for continuity/resistance at all four wheel sensors.

The car is a 1989 325i Bronzit Coupe. I purchased the car used but completely stock.It was an automatic and I converted to manual.

I’ve searched quite a bit on this topic and tried all the basics. Any ideas would be appreciated.

Thanks in advance!

[shoshottz]

ABS light on - E30 gurus please help!

bump. [emoji102]


soundcloud.com/shottzsession

[e30davie]

Bumping after 2hrs and 27mins? sheesh.

soundcloud.com/e30davie

[101]

This is the gold standard for diagnosis ...

https://www.r3vlimited.com/board/showthread.php?t=291172

If the light never goes out after the engine is started and you're sure the ABS relay is good (there's only one BTW), the next thing to do would be to swap the ABS computer module.

[parkerbink]

Did you check the wires leading to the sensors? On my '92 some genius cut the ones on the driver front sensor. I spliced them, no light.

[derber38]

101 - Yes, Mr. Levie's advice is what I have followed so far. Replaced relay in ABS module with known good relay. Replaced with ABS computer module with known good ABS computer module. Neither have solved the issue.

parkerbink - I have not checked the wire leading to the sensors. I have checked for continuity in each sensor. Also resistance measured the same in all four sensors and changed slightly when the wheel was rotated. This is what I expected.
If the wire in harness leading to sensor was broken, I wouldn't expect splicing the wires together would help the situation. However, perhaps there is a way to check the wire integrity from ABS computer module to the sensor connector.

[derber38]

I am aware of the relay on the ABS module.
Would there also be a second ABS relay under the dash of an '89???

[derber38]

Update:
With some suggestions, I found a silver relay located under the dash and above the ABS module. I believe this is another ABS relay. I didn't think this relay was present for the late model E30's but it is there. I pulled this relay and carefully removed the silver cover from the relay. Turns out the internal fuse was blown. I soldered in a fuse per the following YouTube video:

https://www.youtube.com/watch?v=S-49okhvhks

When I plugged the relay back into the harness, the new fuse blew immediately! It blew with battery connected but ignition off. Any ideas where to go from here. Could this relay be bad or is there likely another issue?

Thanks!

[TobyB]

U gotta short.

Find out what that relay is powering... and see what's wrong with it.

t

[derber38]

PROBLEM SOLVED!

The ABS was not functioning due to the blown internal fuse in the relay located above the ABS computer module located under the dash, driver side. I went back and checked my first attempt at soldering in a new fuse into this relay. Not good... it was contacting another circuit within the relay. After more carefully soldering, everything works as intended. ABS light turned off and now properly functioning again. The YouTube video I linked to earlier was very helpful and was another member who sent me a few private messages.

Also note that depending on your car and when it was built, you may or may not have the relay above the ABS computer module. My car was built 12/88 and it had the relay. I check another car built 03/89 and it did not have the relay.

Another note... take the time to review your car's specific wiring schematics.

http://www.armchair.mb.ca/~dave/BMW/e30/

Thanks!