ABS Issue

[Jaantrag]

Hello, new to the forum and new-ish owner of a CQ, and loving it

I have a 91 Coupe quattro B3

The ABS light has been on since i got the car few months back, The #76 relay under the dash does not have the circuit breaker connected, hitting the ABS light on the center console ABS light stays on, but i hear a click coming from under the dash.
now if i plug a circuit breaker to the #76 relay the ABS light wont come on after i turn the key, BUT the ABS pump starts to work, and wont stop unless i turn the key off or hit the ABS button on the center console.
while the pump is running the abs light stays off until i press the brake pedal several times, while stationary, and then stays on

any ideas how to diagnose/test/fix this, or have had similar experiences ?

thanks for your time

[Mikes2]

Someone has removed the fuse because of the pump problem. Needs investigation as to why the pump is always running. There are a couple of relays in there that can fail

[M2ki]

Check relays on the ABS pump.

[Jaantrag]

Both relays seem to be working. Even tried with 2nd set of relays just in case, but still the same result.

[M2ki]

Remove the abs ecu connector and see if the pump still runs.

[Jaantrag]

Been a while since i had time to look into this again, dont really know what i managed to too, but some reason the ABS light wont turn on again .. bulb is good, so could be some broken wires ... other symptoms still the same, pump runnin nonstop..

Remove the abs ecu connector and see if the pump still runs.

not 100% sure what u mean there, but if i remove the wire connector from the pump it wont do anything, or if i remove the connector from the ABS controller under the rear seat its the same, nohting ...

stumbeled on this .. will go thro the pins tomorrow and see how it turns out
http://audifans.com/mirror/www.isham...85/abspin.html

[Jaantrag]

little update..

seems like the ABS controller under the rear seat was busted, tested another controller unit with same numbers, light turned off after starting the motor, so that's good for the MOT, however if i hit the ABS button to disable it, the light wont too anything, pressing it once more it flickers twice and stays off ... light didnt come on during a little 20km trip .. so thats good i quess .. didint have a good test how the braking feels to see if it actually works,

the controller came from a car that been sitting for a several years, and there was some issue with the ABS before that, so could be little faulty controller too .. but seems to be less faulty then my original.