After fooling with my deteriorating stock deck (TD-6141) and finally giving up on it, I decided to install a JVC CD unit in my 87 745. Lacking the time and patience needed to round up a new wiring harness and associated items (I live in a small town), I opted to make my own using bits from the old system.

I chose to remove the stock amp, it is rather puny anyway; of course if you decide to keep this your proceedure will be different and I suppose anything other than an 87 may have different colors, but here is what I found out. Always use a test light first on your own setup, they are only a few bucks, much cheaper than a new stereo...

Main 9-pin plug (female) on black-sheathed harness running to the car:
Left front speaker, white(-) white/yellow(+)
Right front speaker, grey (-) grey/yellow (+)
Constant power, green/red
Switched power (ignition), blue
Ground, fat black wire

Brown 4-pin plug (female) on harness running to car:
Left rear speaker, brown (-) yellow/brown (+)
Right rear speaker, yellow (-) yellow/black (+)

I cut the 9-pin and 4-pin plugs off the old amp and wired them to the JVC harness, note that the wire colors are different on the connector which runs to the stock amp; use the main harness from the car as a reference for the colors given here. Since I'm not using my power antenna I forgot to make note of the trigger wire for it, I believe it may be the seperate yellow wire but don't take that info to the bank :-)

I also cannibalized the faceplate of the dead factory deck to use for trim around the JVC, just cut at the bottom of the buttons and cassette opening, then around the sides and top at the borders of the stick-on face. Remove the sticker first and the knife glides right around, and it also helps to destroy the thing as you go, ie. break apart the plastic between the button holes etc. so that you can score and then break the plastic along your hopefully straight cuts. This leaves about a 3/16 inch gap at the bottom of a standard din sized unit, not at all noticeable and very good for air circulation if you are using a unit with built-in amplification.

Hope this helps someone out there...

shifted