Switched Power in Map Light Housing?

[XanRules]

Howdy.

Due to a nasty rock chip and some resulting de-lamination, I'm planning on getting my windshield replaced soon. I figured this might be the right time to install an auto-dimming mirror. The one I yanked out of the junkyard has two wires - switched 12v and ground.

Is there any reason I cannot tap into a switched 12v and ground wire within the map light housing? I also have a sunroof, so I assume there's a switched wire in there since the sunroof only works when the car is on. This feels easier and cleaner to me than trying to run add-a-circuits.

If this is doable, can anyone tell me which wire/pin is which that I could tap into? If this is not doable, can someone kindly let me know which fuse in the interior I'd need to tap into for switched power? Hopefully I don't already have something running off that circuit.

Thanks!

 

[XanRules]

No? Anyone got a pin diagram I can dig through?

 

[Intuit]

There's like a ten minute delay before power is cut to the dome lights. Your mirror might remain on after you walk away.
(like my accessories here - https://www.fiestastforum.com/threads/guide-amp-remote-turn-on-relay-12v-outlets.29095/)
That can call attention to your car at night and when you don't want it.

If you have a sunroof, it may be better to tap into that circuit since its power requirements are much higher and seems to be cut with the ignition (no delay).

Just make sure the power requirements for the mirror won't overload the circuit's wiring or place it too close to the fuse's capacity. Don't imagine it would though. But as is said, measure twice, cut once.

 

[Intuit]

My opinion on Add-A-Circuit type products...
https://www.fiestastforum.com/threads/psa-fuse-taps-quick-taps.27229/

 

[Intuit]

 

[XanRules]

View attachment 62873

I am laughing at myself because I asked for a wiring diagram, got one, and have absolutely no idea how to read it. I'm assuming the black/blue wire, wherever, that is, is ground, and then anything coming off the switch itself is going to be switched 12v?

Agreed on using the sunroof power rather than map light, though I'm only doing auto-dimming rather than auto dimming with compass and temperature. Also agreed on the add-a-circuits, upon further inspection the boost gauge is tapped into the vehicle wiring and the dash cam is hard-wired without the use of an add-a-circuit using the included hard-wiring kit - that said, I do recall someone saying that there was an empty fuse slot in his interior fuse box labeled "auto-dimming mirror," I just don't want to run all those wires down the a-pillar if I don't have do. Feels neater, tidier, and more "factory" to tap into the map light housing.

 

[Intuit]

It seems you know how to read it after all.

Grey/Yellow (positive) and Black/Blue (ground).

Violet/White feds power to the switch. The other wires are switched. But being post-module, there's a possibility that the power on those wires may be limited.

 

[Intuit]

BTW, let me know what power mirror you select, how the installation experience goes, how well it works, and all that goes and all that jazz.

My windshield was chipped literally two weeks from buying the car new. Had just merged the highway behind another car and a truck passed us up in the middle lane; shot a bullet (rock) off its back tire and that was that. It began to spread not long after. Just haven't bothered to replace in part because I figure the minute I repair it, it'll happen again LoL...

The other part of it is just don't trust anyone to touch my car LoL. (too many bad experiences) For a while I was considering removing/installing myself.

This looks promising...

 

[XanRules]

It seems you know how to read it after all.

Grey/Yellow (positive) and Black/Blue (ground).

Violet/White feds power to the switch. The other wires are switched. But being post-module, there's a possibility that the power on those wires may be limited.

Cool, so basically, splice the switched power from the mirror into grey/yellow and the ground into black/blue and see if it works?

And yeah, I had to get my headliner replaced twice in the first hundred miles and the windshield began to de-laminate soon after thanks to the monkeys at the dealership, I just ignored it until recently when I also got a really nasty rock chip right on the delaminated part and now it's starting to spread and look ugly. I feel you.

Re mirrors, in searching for an auto-dimming one I found a shop online called "Bob's Automotive Mirrors and More" and was incredibly impressed with their customer service, so this is the one I'm going to be getting:
https://www.bobsmirrors.com/NEW-Gen...t-Fits-Most-Vehicles-ADVGENFL8EXP_p_1604.html

It's just auto-dimming with two wires. I don't care about a compass as I have a very good sense of direction (one of the only things I was good at when I was a boy scout), I don't care about outside temperature as that's displayed on both the head unit and the instrument panel, and I don't care about homelink because I don't have a garage. Gentex is the OEM manufacturer for pretty much every rear view mirror on earth, which is why one member on here was able to wire one from a Nissan Maxima into his car with no issues.

I have heard good things about the Wolfbox units, but they are overkill for my purposes (I'm in the process of wiring up a reverse camera using the stock wiring and already have a hard-wired dash cam) and I don't think the way they "clip" onto the mirror looks nice, as someone who likes things to be as tidy and "stock"-looking as possible.

 

[Intuit]

That's what I was trying to determine; whether it was clip-on or full mount. Since it had the camera on the rear was kind of assuming it was independently mounted. When or if the time comes for windshield replacement, will be searching out one that is independently mounted.