It's been about 25 years since I last replaced HUs. These newfangled HUs are a new beast!
I'm using the Metra 7903 harness and mating that to the harness from the Pio 3400 and I've got some questions. From lurking about I've know this is the right place to ask! Here goes...
Is it so nessecary to use a ground point instead of the Metra harness Gnd wire? I've always use the car harness Gnd wire before and never had any issues with noise. Whatever the OEM HU is using is working! If it is best to use a remote Gnd point, what Gnd points can anyone recommend in the M5?
The illumination and dimmer wires (Orange and/or Orange-White) have me puzzled... The Metra harness only has only an Orange wire labelled, "Illumination", while the Pio harness has Orange-White described as, "Connect to lighting switch terminal." They sound the same, despite the mis-color coding. Am I right?
Where is the best point to pick up the reverse signal in the M5? Somewhere in the shifter stack?
Where is the best point to tap into the handbrake line in the M5? The Pio manual is asking for a tap on the positive/high side of the brake switch but doesn't mention if the HU is expecting the handbrake switch to be open (12VDC) or closed (Gnd.) when the brake is on or off.
Ah, such fun!
I apppreciate the help!