Sorry for the long winded essay, but just wanted to give as much background info as I could.
Been struggling with this ABS issue on/off now for about a month, I've read many ABS troubleshooting forum posts/e30 electrical troubleshooting guide/asked local e30 mechanics and can't seem to figure out the issue, so if anyone can share some insight I'd greatly appreciate it!
I've got a 1988 325ix (production date was actually 11/87) with roughly 180k miles on it, bought it cheap, sight unseen, from someone who didn't know what he had. Seemed pretty honest about the condition of the car....wish I wasn't so trusting of people.
Anyways, it all started with the pesky e30 odometer gears being all worn out so I took the cluster out to repair them, upon putting them back in, I had noticed that as well as the 3 harnesses (Blue/White/Yellow) there were 2 sets of wires going to bulb harnesses not attached to the cluster. Got some new bulbs and of course my ABS light was on.
I know that for these cars there are 3 simple diagnostics with the ABS Lights mine being "ABS Light comes on with ignition and doesn't go out" meaning there is a wiring problem, bad module, or bad ABS relay or weak/bad alternator.
Found that info here - https://www.r3vlimited.com/board/sho...d.php?t=291172
I started by pulling the module and the relay out of the car, the relay was bad (the internal fuse was blown) so I DIY'D a fix for it and checked to make sure it was working correctly - it was. Buttoned everything back up and the light was still on.
I knew power was passing through the relay so my next step was to make sure power was getting to the module. After digging around a bit in manuals/forums I found that on the wiring harness to the module;
Pins 10, 20 and 34 should be Ground
Pins 15 and 25 should read 14V
Pin 29 should read .69V
Found the electrical troubleshooting guide here. Really great resource, I have it saved on my iPad so I can pull it up quickly in the garage.
https://forums.bimmertips.com/viewtopic.php?t=134
Everything checked out except pin 15 was reading at 1.5V. According to the schematics, Pin 15 is being provided voltage from the Alternator. Took my voltmeter to the back of my alternator and found that it was only outputting 1.5V. Pulled it, got it bench tested and determined I needed a new voltage regulator. Popped a new one in and it was outputting the correct 14V. Went back to Pin 15 on the wiring harness and that too was outputting the 14V.
Once again, buttoned everything back up, went to start the car and....light is still on. So it must be the module right? Scoured the web to see if ABS modules were IX specific (still haven't found a definitive answer) but went ahead and bought a used module off of a '88 325ix (seller said it was working when pulled from car) just to be safe. Just got it in the mail yesterday, plugged it in and still Lights!
What are the chances of two bad modules, am I missing anything? Should I start looking at ABS sensors, (even though diagnostic light would not turn on until being driven for bad sensor)
Any help would be appreciated!
Cheers!
Been struggling with this ABS issue on/off now for about a month, I've read many ABS troubleshooting forum posts/e30 electrical troubleshooting guide/asked local e30 mechanics and can't seem to figure out the issue, so if anyone can share some insight I'd greatly appreciate it!
I've got a 1988 325ix (production date was actually 11/87) with roughly 180k miles on it, bought it cheap, sight unseen, from someone who didn't know what he had. Seemed pretty honest about the condition of the car....wish I wasn't so trusting of people.
Anyways, it all started with the pesky e30 odometer gears being all worn out so I took the cluster out to repair them, upon putting them back in, I had noticed that as well as the 3 harnesses (Blue/White/Yellow) there were 2 sets of wires going to bulb harnesses not attached to the cluster. Got some new bulbs and of course my ABS light was on.
I know that for these cars there are 3 simple diagnostics with the ABS Lights mine being "ABS Light comes on with ignition and doesn't go out" meaning there is a wiring problem, bad module, or bad ABS relay or weak/bad alternator.
Found that info here - https://www.r3vlimited.com/board/sho...d.php?t=291172
I started by pulling the module and the relay out of the car, the relay was bad (the internal fuse was blown) so I DIY'D a fix for it and checked to make sure it was working correctly - it was. Buttoned everything back up and the light was still on.
I knew power was passing through the relay so my next step was to make sure power was getting to the module. After digging around a bit in manuals/forums I found that on the wiring harness to the module;
Pins 10, 20 and 34 should be Ground
Pins 15 and 25 should read 14V
Pin 29 should read .69V
Found the electrical troubleshooting guide here. Really great resource, I have it saved on my iPad so I can pull it up quickly in the garage.
https://forums.bimmertips.com/viewtopic.php?t=134
Everything checked out except pin 15 was reading at 1.5V. According to the schematics, Pin 15 is being provided voltage from the Alternator. Took my voltmeter to the back of my alternator and found that it was only outputting 1.5V. Pulled it, got it bench tested and determined I needed a new voltage regulator. Popped a new one in and it was outputting the correct 14V. Went back to Pin 15 on the wiring harness and that too was outputting the 14V.
Once again, buttoned everything back up, went to start the car and....light is still on. So it must be the module right? Scoured the web to see if ABS modules were IX specific (still haven't found a definitive answer) but went ahead and bought a used module off of a '88 325ix (seller said it was working when pulled from car) just to be safe. Just got it in the mail yesterday, plugged it in and still Lights!
What are the chances of two bad modules, am I missing anything? Should I start looking at ABS sensors, (even though diagnostic light would not turn on until being driven for bad sensor)
Any help would be appreciated!
Cheers!
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