Got my hands on a relatively well-cared for 99 T, so I'm adding a few upgrades for creature comfort (my wife will be using this car mainly). We decided a rear camera was not necessary, but she wanted parking sensors in the rear. So I purchased a basic system with 4 sensors, control module, and speaker. Everything is straightforward except the 12 volt supply from the backup lights. With the way the rear hatch is built the electrical wiring has to go up into the rear roof. But from there where does it go? I'm hoping it heads back down one or both sides which would make access easy. If it follows the color coding from the lighting module the left side wire should be white/yellow, but I'm experienced with a VOM so finding a live wire is not an issue, especially if there's a connector to use as a test point.
My daily driver is a 2000 528i sport, manual. I'm way past the point in life where performance upgrades mater to me, so that car is very close to stock. When I bought it 4 years ago I spent the first 6 months pulling off bling the previous owner had put on it, to get it back to a more stock appearance.
My first BMW was in 1969; it was a 1600, what became the 2002 body, with a 1600 cc engine.
Appreciate any information and help I can get.
Found this from a guy changing out his entire interior. Shows wiring looms going up into the ceiling on bother sides. Hopefully one or both have the wire I need. Time for a little snooping with the VOM. Also plan to test install the PDC module once I identify the correct wire, since this wine in the chassis comes from the notoriously-cranky LM
BMW-e39-interior-swap091.jpg
Lee
Last edited by lchurch; 10-22-2018 at 04:23 PM. Reason: new info
Two sources: several posts about the ceiling speakers having a set of hatch wiring that ran on top of the speaker, under the roof. So that raised the possibility of being able to tap in there and just run a wire back to the hatch opening and down the trim to the equipment space on either side.
Second source was a guy that stripped the interior in order to change color. The pictures he posted confirmed what I suspected: on both pillars at the rear doors there is a branch of the wiring loom that heads up into the roof area. According to the BMW specs the wire for the left BU light is white/yellow; if I find one in that bundle I'll slap a VOM on it and confirm 12 V when the car is in reverse. Since the LM has a history about being cranky about changes to bulbs and wiring, I'll also test install the non-OEM PDC control module before I bother to run my wires and find out BMW has sabotaged this project. Otherwise I can just run my wire over the wheel well and into the equipment bay.
Where does the factory PDC hook into the wiring? There are retrofit kits so there's probably an unused connector somewhere.
Found another option: A license plate surround that has 2 adjustable PDC sensors in the frame, along with the electronics. Since everything is now contained in the hatch, I plan to tap the left BU wire in the hatch wiring loom to provide power. The unit has a small (2" ) speaker to sound off distance, so all components will be in the hatch and wired properly.
Business has intruded on my schedule, but I hope to have this done and buttoned up in the next week.
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