Question on wiring to aftermarket head unit
 

Hello, I'm a new member here and am in the middle of installing a complete aftermarket system in my 2005 X5 that had oem Nav and no DSP. I gutted the entire OEM system. I've installed a JBL MS-8 amp/processor, a JL Audio sub amp and a sub. All that wiring is done! I've installed the double-din head unit bracket purchased on ebay (that's a story by itself). Now, I can't seem to find where to pull the power/ground and switched power from. I found a wiring schematic for the car. I could go to the fuse box. Can anyone who has done this tell me if I can simply cut and solder 3 wires from the nav head unit/ monitor harness and which ones they might be? I'm this close to having music in my X again!

are you looking for the power just for the head unit or for the whole system, including the amp? in either case, you should know your power requirements (wattage/amperage) in order not to overtax existing wiring - most existing power wires are "broken" in sections, and feed certain portions of the sound system with individually rated fuses and not one single fuse feeding the entire system... as a result, you can see several fuses covering one component on the fuse legends...

in the worst case scenario, when you need to power up the whole system at once, i would recommend drawing power directly from the battery with its own dedicated fuse, and regulate that power with a small electronics relay that is connected to a switched circuit...

welcome to the board...

you know... no pictures... then... it did not happen... lol...

Specifically, I 'm looking at the wiring harness that went to the stock navi head unit. I've wired the amps up directly to the battery but was planning on tapping into the stock harness to power the Pioneer Avic I'm installing in dash. I need to know which wire is power, ground, the accessory power and wire for the dash illumination. Anyone? Thanks!

In accordance with DIN (Deutsche Institute fur Normung - German standards authority) most wires that are related to the ground will be BROWN or have BROWN color in them, along with another color streak (if that ground is for a specific module), and most power wires will be RED or have a RED color with another color streak (if that is power on ignition, power on LAN, power for whatever...) BMW AG adheres to these standards - therefore, using a miltimeter, check the brown wires to see if they are shorting to the chassis, and then check the wires with red in them to see what kind of power they carry... if you can find a THICK wire, chances are that will be part of the power supply to the module, so you might be looking out for those...

I dislike hacking into wire harnesses if I can avoid it. I did not realize they were included when I got my APPRADIO3 from Crutchfield so have an extra set which are posted in the marketplace here.

Receiver Wire Harness For select 2001-up vehicles at Crutchfield.com

Metra 40-EU10 Antenna Adapter Works with select 2000-up vehicles — Motorola male to factory antenna female at Crutchfield.com

Thanks for the input guys! Since this is a one way trip, no going back to OEM in this car, I spliced into the harness and found the constant power, ground and illumination wire. I know the white/violet wire is supposed to be switched power, but it's on all the time or at least when I'm testing it. Any suggestions for pulling a switched power wire (from another accessory, the heater controls, etc. Or do I have to disconnect the battery or some other technique to reset whatever relay is keeping that wire hot?

Otherwise the radio will be on all the time.

Could be power on LAN. Test that wire 20 minutes after any activity on the bus/after car is asleep

When I did my AR3, it worked for 15 or so minutes until I fed power to the CD player in a second wire. I'll take a picture when I can.

Yes, mine is still hot after an hour, go figure. Didn't have a problem with the OEM HU staying on..

I just reread your initial post.

I have DSP & am using the factory amp.