ABS is dead, light never comes on

[emi]

The car was jumped a little while ago, and the moron that did it crossed the jumper cables. The abs relay didn't burn, because the fuse inside it had been re-wired.

So, now, the ABS light doesn't come on when the car is started, and the abs doesn't work. I replaced the ecu, and the relay, just in case. I even tried them in my own e30, so I know those 2 components are good. Fuse #6 is good, and everything else on the car is good.

Bentley doesn't have a circuit diagram for the ABS, probably because they don't want me messing around with it.. that's gonna stop me, yeah.. Any ideas where I should start?

[James Crivellone]

For future reference, ALWAYS list build month and year, as BMW changed wiring throughout the years on the car.

Get me the above information, and I can get you the ABS Schematics.

[emi]

It was made in 07/88. Thanks a lot.. schematics will be very helpfull, i really appreciate it.

[James Crivellone]

It was made in 07/88. Thanks a lot.. schematics will be very helpfull, i really appreciate it.

http://www.scchosting.com/e30/e30_88.pdf

Alright, have fun =)

[emi]

awesome, thanks

[emi]

update

I started diagnosing it, but, shortly after I started I noticed there's no abs indicator light bulb. Unless bulbs just disappear into thin air, someone removed it. And the only people touching that car were myself, and Nikolas Motorsport. I took the car in to get A/C serviced a year ago, after having the ABS fixed during the winter.

So, I put in a new light bulb, and, amazingly enough, the light stays on constantly.

I went on with the diagnosis, and checked continuity between the ECU connector and the hydraulic unit connector (all seems good), as well as power and ground to both. I haven't found a fault, however, I noticed that the main relay on the hydraulic unit doesn't click on. The relay should be turned on by the ECU, via ground on pin 27, I think... pin 2 on the hydraulic connector.

That's as far as I got... Are there any obvious things I should check?

Also, since the indicator light hasn't worked in a while, my initial assesment is probably wrong. The abs didn't necessarily stop working when the car got jumped.

[ryan_george]

I was going to suggest you check the bulb, but looks like you're already there.

[emi]

It's finally fixed. The winning combination was new bulb, new relay, old ecu. the ecu i got off ebay didn't work. So, yeah, the missing bulb and the bad ecu confused me... but it's all good now.