So far this project has gone about nowhere..
I'm torn between a camera, the hole-less electromagnetic proximity systems and the ultrasonic systems.
I did track down the reverse light power source - it's the blue/black wire going to the taillights. I've taken apart the wire duct going from the tail-gate to the body.. there is room on the passenger side one for another wire or two.
Decision points:
Camera:
It's gonna be a PITA to mount and wire
I've looked at wireless - and ones that work (and apparently many don't) - still are a bit marginal in performance, and the ones I found mount to the licence-plate screws. Which is a problem because it puts the camera in the way of the rear-hatch release handle. They also still require at least a power feed into the vehicle, and there simply aren't any handy holes going through the tailgage, and I'm not about to make any.
Looked at one that's being sold on Ebay - camera alone - that replaces one of the license plate lights (and it even has a plate light built into it.) Still requires a power feed and a video out feed - that would then have to be strung up through the duct that surrounds the hatch-hinge, down through the body and all the way up to the front.
They all use a remote monitor - which really looks added on if it's plopped on the dash. I thought about putting one inside the sunglass cubby overhead, which would be a pretty neat spot since there is also switched power available in the roof console (for the Homelink unit.) BUT - if used with a wired camera - still have to get the video cable up there and down and all the way to the back to the camera. That's a lot of taking stuff apart to run that cable.
Prices - I found the AudioVox - which got almost decent reviews for $100 on several websites. A place local to me has it for full retail - $150. BestBuy may or may not have it in stock. This is a wireless one, but it only comes with the license plate mount camera. And it apparently comes with a hard-wire cable in case the wireless doesn't work. http://reviews.cnet....7-33520636.html
Wonder how the camera would work through the rear window? Probably not all that great since the tint is fairly dark..
Electromagnetic induction units: (http://www.sportsimp...nbuelsekit.html)
Seem like a good thing, no holes in the bumper. Easy installation (or as easy as it gets - which isn't awfully easy.) Have to remove the bumper - biggest part of the job.
Problem is - reviews on their performance have been uniformly miserable. Most of the reviews I saw suggest they are simply a bad idea that doesn't work. There are known problems with having the real bumper in close proximity (the large metal one under the bumper cover.) It might be possible to mount the antenna for this type far enough away that it might work.
No visual display - simply different beep patterns - but I'm used to that from our BMW so that's OK *IF* it works.
Price - found this one for $10 with free shipping at one website. I might just order one because it's so cheap.. http://cgi.ebay.com/...r-/310315976656 Walmart actually has this system in some of their stores. Dunno if that's good or bad. Also dunno the price from Wally - it's not priced on line.
UltraSonic sensor systems:
This is what Porsche and every other manufacturer uses.. must be a reason for that. It likely isn't strictly price driven since the electromagnetic would be cheaper and simpler to manfacturer and install. There was the option with the Cayenne to not only have this - but also have the tailgate mounted camera system (double-bagging)..
Requires drilling holes in the bumper. I've installed these before (on a BMW M3) - and the first hole is the scary one, the rest aren't so bad. Bumper must be removed.
One place I visited that installed this sort of system (an auto-audio store, called.. AutoAudio..) claimed this wasn't possible on the Cayenne since the real bumper is so close behind the cosmetic cover. I did some careful looking - and they were FOS. The factory mounts the sensors in the flattish band near the top of the bumper (shown in the photos above), laying under the car and actually looking - that is a clear area ABOVE the real metal reinforcement. Plenty of room for the sensors.
Colors - found some on ebay with sensors in various colors, including one "ice-water silver" - which looked a lot like Iceland Silver.. so that would be OK except it was coming from China, and they allowed themselves about 30 days to deliver it. My attention spam isn't that long. I couldn't find any in the US that had the range of colors available on Ebay.. but did find some that could be painted. Problem there - I can't find a car touchup spray that is even close to Iceland Silver (it also took extensive research to even find a Porsche touchup kit for this color..)
Noplace near me carries these - except the place that claimed they wouldn't fit. And theirs are in black, and they claimed they couldn't be painted. And they wanted 10x the amount for the kit then it cost on Ebay. So that's not a winner.
This would not require any wiring inside the tail-gate, or through the hinge assembly - which is a GOOD THING. All the wiring would be stationary - from behind the bumper, into the body cavity on the right side where the Bose amp and CD changer live. Backup light wire is available right there..
These are available with "wireless" and an LED display http://www.sportsimp...sensor-kit.html or much simpler with just the beep-beeper http://www.sportsimp...di4flmobas.html - I'm much more likely to get the simpler one, just because I've had the other one and the lights were pretty much a distraction. More for bling then use..
Thoughts? Anyone BTDT and want to share? I saw on 6-speed-on-line the chap (I think he posted here also) who modified his PCM to take a video in signal (with a $90 module from the UK) - which was pretty neat, but still requires mounting a camera somewhere outside and getting the wiring inside and up to the PCM.