I have an 1989 535i that did not come with alarm-ready wiring. I have a factory alarm from a 1992 535i. I also purchased, from the dealer, an alarm wiring harness for non-alarm-ready E34's. This dealer harness is fairly simple, it tees into a couple of existing connectors.
My question is: Has anybody ever done such an installation, and where are these elusive connectors? BTW, I already looked under the back seat.