I think the reverse wire is probably for people integrating a reverse camera. That is probably how the system knows to change the display. I'm guessing you don't need this wire if you don't have or plan to have a reverse camera.

 

A backup camera? Cool! I don't think that even the European unit supports that!

I would have guessed that the "reverse" signal is there to simply add a direction (forward or backward) to the speed signal....

 

Good to know that this type of installation has been done before successfully. But where exactly is the location of this "VSS wires at the ABS brake module"?

Does using the accessory/NAV jack work? This seems like an easier solution? But I have no idea if there are actual wires on the jack as indicated on the diagrams.

And yes, the Garmin unit does have an extra RCA port for backup camera or DVD. It even plays Audible.com's audiobooks and has SD slot for playing MP3s.

 

Another issue about the Garmin which I didn't phrase clearly:

The unit comes with one 12-volt cigarette adapter cable and a regular A/C power adaptor. None of these power source options presents a pleasing or clean install to the vehicle, as a power wire has to be run from the back of unit all the way to the center console area. How do I hide the power cables? I don't want a big cigarette adaptor permanently sticking out of the accessory outlets area with a long wire dangling off, it's just ugly.

Is there a way to cut/splice or use "add-a-circuit" type procedure to tap into the wire of the accessory outlets behind the dashboard?

 

Sure, you can either run a wire directly from the battery (with an inline fuse of course) or you can use the easier method of a fuse tap. The fuse block is in the base of the center console/dash in the passenger footwell and is easily accessed from behind the dash. That is how my Sirius plug and play unit is powered.

 

Since the Garmin unit comes only with a cigarette lighter plug, is there a "converter" that allows the lighter plug to be connected to a fuse tap?

 

There is a converter....it is commonly called a pair of wire cutters. Snip Snip. Off comes the 12V plug. Strip the coating off the two wires (making sure to note which is hot and which is ground I can't remember but I think the one going to the "point" is hot and the one going to the "sleeve" is ground). Then you buy a fuse tap and the corresponding wire connector which crimps on to the hot wire. You then slide the connector over the fuse tap and insert it. The ground then goes to any grounded metal in the vehicle.

If you are not willing to cut off the "plug" (in order to take it with you to other vehicles) you could buy a spare 12V outlet for a car and a couple of wires. Then wire the outlet to a fuse tap as described above and stick it inside the dash. That way you have a quick disconnect, you can take the unit with you, and it is all hidden. The back of the dash is so open and accessible that this isn't a bad idea. Since there is a fuse in the plug already you wouldn't need a fuse, but better safe then sorry.

 

Just make sure the plug has no regulation or step down in it and that it delivers 12V to the Garmin. Its very unlikely for there to be a voltage converter in the plug, but you might as well make sure. Easiest way to be sure would be to take the plug you've cut off make sure the wires are far apart, plug it into the cigarette lighter and see if the voltage at the wires is somewhere around 12V or so. It could be as high as 14 if the car is on.

Of course you can't back out of that "test"

 

For my Garmin, the cigarette lighter plug not only converts the voltage down, it also includes a speaker for verbal turning directions. My Garmin expects 5v, the same voltage it gets when plugged into an USB port.

 

If it does convert the voltage down, then I recommend my second solution of wiring an additional outlet behind the dash.