Question for Mike Holbrook....

[George Mann]

Mike,
Do you recall when you connected your later model BMW CD head unit if you only connected the + speaker terminals to the connector you purchased/sliced into your car harness? Later BMW head unit connectors have leads for the (-) speaker terminals as well as (+) terminals. My guess is one should only connect the (+) speaker leads off the back of the radio and isolate the (-) leads and not connect them to the car harness...not unlike installing an aftermarket head unit that has provision for connecting (-) speaker leads.
Please let me know if you recall.
Thanks,
George

[mholbrook]

Sorry, I can't remember. I'm sure I connected the plus terminals to plus but I may have ganged the grounds together and grounded them witht he radio ground. Sorry no help but it wasn't to hard to figure out I guess....since somehow I got it working! Probably blind dumb luck on my part.

[George Mann]

Guess I will start first by not ganging the radio (-) leads like I have my Kenwood wired which works beautifully. Believe on negative ground car systems, there should not be any ganging of (-) speaker wires together to connect with a common ground "to the radio". The stock radio that came on my 90 E-32 has only positive pins from the harness to the radio but if you look close, the radio itself has negative female connector recepticles that go unconnected from the factory. Believe on negative ground radio's with a grounded post amp, the negative speaker leads are grounded to the vehicle's earth and that is how the circuit is completed. It is perhaps wrong to gang the negative radio speaker leads together and attach to the vehicles earth or redundant or both. If someone knows for sure, please post.
Thanks,
George