Wiring a mirror upgrade.

So my son gave me this swanky Donnelly rear view mirror that has compass and temperature display. I ran the wires under the headliner and down the drivers side so that the reappear down by the E brake. According to the wiring directions, hooking them up requires a ground and a power connection only. I’m can hook the ground side up with no problem, it’s the power wire hook up that I question. Where would the best connection for the power wire be please? Be painfully specific please as that my knowledge of even basic auto electronic wiring is extremely obvious.

 

Do you currently have a factory overhead compass / temp display? That would be where I would splice into. I don't see how the temp would work without tapping into the ambient temp sensor unit. Can't be just power and ground.
@caribe makaira

 

You will need to run temp sensor wires and add a temp sensor somewhere as well but most trucks have a factory plug behind the overhead console that has power and ground wires.
If that plug is there the wire colors are:
Red (Full Time Battery Power)
Light Green (Ignition Power)
White/Black (Ground)
See also this thread.

 

No I do not have a factory C/T mirror I’m starting from scratch. This mirror appears to have the sensor up where the mirror attaches to the windshield. When I acquired this mirror, my factory mirror was in place and this new mirror didn’t fit on the windshield adapter, it was too big. My son in law and I attached the wiring directly to the battery, outside of the truck to test it and the temp and compass were accurate. Since my windshield has been replaced I was able to choose an adapter that fits this mirror so I’m now ready to wire the new mirror.

 

See if you have the factory plug (see my post above), if you do you have power and ground right there.

 

I’ll check. Unfortunately I’m OOT at the moment for a funeral but will be able to get into it further tomorrow evening. Thanks for your input and I’ll be back to you in a day or so.

 

if its only a 2 wire hookup, its sounds like it has a builtin temp sensor which will only takes the inside cab temp. Not really a deal breaker and still an improvement in your no temp/ compass setup. I use the compass more than the temp to confirm I am not going the wrong direction on the freeway. lol.

 

I see what your saying.

 

I’d use acc power or ignition power.(this way it will only have power with the ignition in acc or if the ignition is on.) But I’ll tell I’m not a fan of splicing into factory wiring. Maybe use a tap a fuse.

 

I understand what you’re recommending because of the selective power but again, how do I identify those wires down near the E brake where my wires come down?

 

If you use a tap a fuse. You’ll go directly to the fuse box, the cover is marked as to which fuse is what.