Whats the little box under our rear view mirror?

[BrianDye]

My XLT doesn't have the auto-dimming rear view, so i'm ordering one. Just to confirm the mount matches, I went out and verified.(It does) There's a little box "snapped" onto the mirror mount (but not part of the mirror) with a small 4 pin wire harness plugged into it, and the unit has a button. There are no visible markings or anything on this.

What the heck is it?


Edit, found my answer on the F150 forums
*I found out its part of the compass, and the button is like the reset or program button

 

[BrianDye]

Snagged some screenshots from eBay:

 

[beauboy]

My 07 Limited has the box also. I could be wrong, but I think that's for the auto headlights.

All Ex-experts - Let me know if I'm wrong.

Thanks.

 

[BrianDye]

I edited the first post, I figured out it was for the compass. The auto headlight sensor is part of that little black bubble on the top/middle of the dash where the security light also flashes when its locked.

 

[Trac Marks]

FWIW, I replaced my self-dimming factory mirror for a Homelink unit. The new mirror is significantly larger, as is its mounting stem, so this black box of mystery could no longer ride on it. So I temporarily mounted this compass box to the windsheild with double sided tape as shown in the picture. Ultimately I removed the overhead console and mounted this box just behind the dome light assembly. It fits like a glove and doesn't rattle. There is plenty of wire to easily fish it behind the headliner. The compass is still 100% accurate. Since the backside of the map light housing gets stupid hot with the incandescent bulbs, I'd suggest upgrading them to LED while you are in there. Otherwise you might just melt this box.

If you unplug and remove this box entirely, instead of a compass heading next to your odometer, you'll get an annoying dash line, like this: ---

Just thought I'd share incase anyone is interested in upgrading their factory mirror.

 

[BrianDye]

Just upgraded my mirror to the OEM auto-dimming one. Grabbed it for $30 on eBay, so the module snapped right on. If you cut the tape/covering off the wire harness, the wires go all the way down the A-Pillar, so theres more than enough to get creative. One of the first mods I did to my 06 was an LED conversion The stock bulbs were garbage!

Just ordered bulbs to do my cluster, HVAC controls, and rear HVAC controls yesterday.

I really like that home link mirror, almost got one on eBay until I found the OEM mirrors so cheap. Im going to try to find a home link console, my garage door opener is so clunky and ugly looking.