It's pretty straightforward. Depending on the characteristics of the new in-dash unit, you can connect the new radio directly to the factory wiring either one of two ways: 1. If the new unit is "High-power" floating ground type (characterized by instructions to not hook the speaker grounds to chassis ground), connect e ach of the four speaker "+" wires to the appropriate wire on the car's harness. Connect each "-" wire from the car's harness to the chassis of the radio, _not_ to the radio "-" wires. Leave the radio's "-" wires disconnected and insulated.

2. If it is a low-power common ground radio, (this is exactly what the BMW radio is) simply connect each pair of wires from the car's harness to the mating radio wires. The wires with the brown stripes are the "-" wires from each pair.

With some E34's, connection type #2 will also work with radio type #1. I don't know for sure with the '91. I do know that my '93 (Pioneer) requires connection type 1. If you're not sure, use connection type #1. It's a bit more hassle but will work with any year car and either radio type.

Best Regards,

Bob Hazelwood
VP Product Management, a/d/s/

'93 525i 5-sp, Sharked of course.

> From: Carl Jerritts <carl_at_info2000.net>
> Date: Mon, 27 Jul 1998 12:57:59 -0600
> Subject: <E34> Car Stereo Questions
>
> This has probably been covered a million times but here we go again:
>
> I am helping a friend put an in dash CD Tuner with speaker level outs
> into his '90 535 which has the factory amplified system and want to
> retain the factory amplifier and speakers. Any good tips on this so I
> don't have to reinvent the wheel....please!
>
> Thanks & Regards,
>
> Carl Jerritts
> '91 Dinan 5(New ignition coil and no more power loss!)