Backup Camera Activation

So many people have mentioned that they would love to take a peek behind them while driving that I thought I'd take a look at the wiring diagrams. For those that have the 2006 Wiring Diagrams, I'm looking at em01r40.pdf. It appears that +12 volts is applied to a red wire by a backup relay, which turns into a black wire, goes to J36-C junction connector, and splits 2 ways: one lead goes to the Nav ECU, pin #20, and the other to the Multi Display, pin #21. Both are labeled "REV" on the diagram, evidently indicating REVERSE. My question is this: why does the NAV need to know when you're in reverse? Does the operation of the NAV change when you're backing up? Just curious.
Anyway, it looks like it would be fairly simple to apply +12 volts to that line to tell the MFD to switch to the rear camera view. Anyone brave enough to try it? :blink:
I'd probably recommend cutting the wire, and using diodes, to avoid having the power backfeed, in case that would cause an issue, especially if it changes the NAV operation.
Jeff O.
Hobe Sound, FL

 

Ohhhh, but MY car is only 2 weeks old. I don't even have the guts yet to remove the glovebox for the EV switch mod. :blink: I'm quite a proficient hacker and mechanic, but I'm still squeamish about touching my new toy!

 

Thats what I sort of figured, which is why I suggested using diodes. I guess I'll have to read the FAQ on removing the display, and see how tough it would be to pick up a hot wire to trigger it.

 

OK, I finally decided that I should be the guinea pig, since I proposed the way to do this. My car is a 2006 package #3, without NAV. So, the directions, and plugs may look slightly different if you have NAV:
1) Install a pushbutton switch in the dash, ala Evan Fusco's directions for installing the EV switch, using one of the blank plates in the dash:
http://priuschat.com/forums/kb.php?mode=article&k=5
My Radio Shack was out of the one he specified, so I had to use the more conspicuous red one shown here:
http://www.dsmchips.com/~keydiver/switch.jpg
2) Follow the directions in Chris Dragon's stereo install pdf to get the back of the MFD.
http://www.chrisdragon.com/downloads/Stere...us,%20v1.03.pdf
Follow his steps carefully up to his page 7. You don't need access to the stereo so you don't need to remove the compartment below the radio, or the radio itself. Once you have removed the MFD, skip from page 7 to page 9 to reinstall the panels in the proper order.
This is what the back on my MFD looks like:
http://www.dsmchips.com/~keydiver/display.jpg
The plug circled is the one that has both +12 volt power and the REVERSE wire on it. You will notice that it is the mirror image of the MFD shown on the CANVIEW site, but the power wire is the same, a gray wire on pin #2:
http://www.hybridinterfaces.ca/installNONAV.html
3) Here is a closer view of the 2 wires we need to tap:
http://www.dsmchips.com/~keydiver/plug.jpg
The gray wire, pin #2, circled in red, is the +12 volt power to the MFD, which we need to "vampire-clamp" to send power to the switch.
The pink wire, pin #21, circled in black, is the reverse trigger wire from the backup lights to the MFD. According to my schematic, on a NAV-equipped car this is a red wire. This wire needs to be cut, and a diode installed into it with the banded end toward the MFD, to keep our new switch from turning on the backup lights.
4) Diode installation (note: this can be any 1N400X series diode, like 1N4001, 1N4002, etc):
http://www.dsmchips.com/~keydiver/diode1.jpg
Remove the electrical tape wrapped around the bundle to give you more wire to work with, and cut the pink wire. Slip a piece of heatshrink onto the pink wire before soldering. Also, you will want to solder one of the wires from your switch to the banded end of the diode, the end connected to the MFD connector:
http://www.dsmchips.com/~keydiver/diode2.jpg
Use a heatgun to shrink the heatshrink onto the diode.
5) Use a "vampire-clamp" to connect the other wire from the switch to the +12 volt gray wire on pin #2:
http://www.dsmchips.com/~keydiver/both.jpg
6) Follow the directions on the last page of Chris Dragon's stereo instructions to reassemble your dash.
That's it! You can now push the button any time you want to see the rear camera. However, as someone pointed out, it is an EXTREMELY wide angle, like a fisheye lens, so anything more than 50-100 feet behind you is invisible.
As an added point, I've now been thinking about how easy it would be to hijack the camera's video input to the MFD, and trigger it to watch DVD's on the MFD display! B) I may play around with that just for fun.

 

I'm fairly sure that the camera interface is an analog, baseband video input, hopefully NTSC. (This is why the CANVIEW RGB interface doesn't work with the 2006 cars) The schematics show 4 wires to the camera:
Pin #28= Shield = V- (Video negative)
Pin #27= Red = V+ (Video positive)
Pin #30= White = Camera Ground
Pin #29= Black = Camera + Power

If I had a portable DVD player I'd jack it into the AUX audio, and try connecting the video into the MFD to try it. Playing DVD's on the MFD would be cool! B)