ABS light in '93 VW passat

This seems to be a reoccuring problem here with all types of cars.

I've heard of VWs being kind of wierd like this too.

The installation involved replacing the HU. I did not cut or splice into any stereo wiring at the HU or at the factory amp. I used the harness, but I only used the three power wires. It was easy enough to run new speaker wires, so that's what I did. I spliced into the front speaker wires under the dash because I left the factory tweeters alone and only replaced the door speakers.

The factory amp was removed and is still around, I recomended that it should be put back in because it might have some odd ball circuitry tied into the OBD1 system. It sure looked like it had much more wiring than the stereo actually needed. That's why I left the harness alone.

The front speakers will be connected to the factory amp and the HU if it's re-installed, hopefully the VW amp won't power up without a signal from the VW HU, I'll be cutting those wires any ways, just to be sure.  The impedence of an unpowered amp output is much more than the speakers, so the HU should be ok, but that seems kind of hack to have it hooked up that way. I don't like to cut wires, but I can tape them together (insulated) incase someone ever needs to re-connect them. All of my connections are soldered, so I was least interested in tapping 16 wires at that ridiculous amplifier harness.

The aftermarket harness came with 12v remote and antenna wires, but they weren't in the plug. I'm sure there is nothing in the car that needs them, so the only remote connection was from the HU to the aftermarket amp. The antenna adapter had a 12v connection on it though! Strange, I didn't ask why I just connected it. Is this a signal amplifier or active filter?  You can tell I don't do many VWs!

If anyone has anything to add, please do! 

Besides that ABS light, the system came out nice! This car was a pleasure to work with, I'd like to install more systems in VWs.

-Thanks 12v.com , the ACC color code was very helpful. instead of playing with my MM and ignition key for 5 minutes, I found my wire and had it done. This site is the greatest!