dakar

I'm in a position where I'm going to 'aquire' an auto-dimming rear view mirror from a '98 Grand Cherokee. I think it deserves a new home....in my 3500. Its a bit smaller but the dimming effect is worth the size reduction.

The real question is anyone have any idea how these things might actually work concerning the wiring? Need to get out there with a meter and see what i can figure out, maybe some of you guys can save me some figgerin'. Its fed by 5 wires up under the headliner.

Without even looking at it I'd guess;
ground
power for the mirror
one (maybe 2) to feed a relay of sorts when the headlights are off to disable it
the other (two?) who knows....

It has a built in sensor on the side nearest the windshield that I'm assuming determines if its dark enough outside to activate, the other sensor is on the reflective side that when bright light hits it the mirror darkens.

I just can't see my way to pay $200 for an aftermarket or like $300 from the dealer.

Anyone fool with one of these factory jobbers and know what the wires are really for? Should be an easy enough hack to make it work.

04ctd

here's the real Q?

how do you make it darker? it's too bright for me, eyes are crappy, so I flip a regular mirror down twice. can you adjust these things?

seems like, if the kid sits in the middle, she blocks the cars behind you from making the lites dim.

IRT ur Q?, if it has interior/lamps on it, 3 wire are for them: ground, hot, and switched (hot to turn on by switch, and switched to come on with interior lights)

Stamey

You know, I have one of those, stock, in my truck. I dunno if the the factory tinting or what, but I've never seen it work (there's a little light on up there though). The factory tinting is not drastic. If you've seen it, you know what I'm talking about. I think I opened the sliding glass window in the back once, to see if it would work, but it didn't. Could it be broke?
Does anyone's auto-dimming mirror actually do anything?

Chris

Lil Dog

Our minivan (town and country) has the dimming rear view inside and drivers outside mirror. Work pretty much all the time and are really handy on the highway.

I wish you could get the drivers mirror to dim like the van, cool feature.

jfpointer

Stamey,

Mine works, sometimes too well. In heavier traffic, it gets so dim that it's hard to keep track of all the bogies, so I turn it off.

Dakar,

I looked up the wiring for the mirror in the '02 FSM, and the one in the Ram only uses three wires, not five. 1=12 volt, 2=ground, 3=feed from backup switch. The one from the GC must be checking something else, too.

dakar

Okay great...thanks for the input guys...

This one actually works extremely well, even with the dark tint all around the GC, with of course the exception as noted . No interior lights on it or anything...so no idea what the rest of the wires control, I know its not for the temp sensor for the overhead or anything as it all works wit the mirror unplugged so my concern level about them reduced drastically.

Gonna hit a parts store at lunch and grab a $20 special that will magically replace the existing mirror and hack on it this weekend... I'll get that critter to work or let the smoke out trying....

04ctd

smoke is annoyingly difficult to catch once it gets loose...

dakar

JWIW, I finally got around to getting the wiring sorted out and in place.. Hooked it up a couple a days ago routing wires under the headliner..... IT WORKS! Have no idea what the extra two wires were for when it lived in the GC, but i managed to keep all the smoke in and it works very well even through the 35% tint on the rear window.

Thanks for the input folks.
Dave

Nevada

One of the wires (sorry I couldn't tell you which one) ties to the back up lights to disable the dimming feature while you are backing up.

Redleg

Does it have a compass or thermometer built in for the extra wire?

dakar

No idea if the compass could be living in it... the GC had one, always assumed it was built onto the board for the overhead display. Nothing extra added to this mirror itself that's visable, it didn't want to come apart very easily so i let it be...just wired up the 12V and the two ground wires and it works... never thought about there being a disable circuit for the backup lights, thanks Nevada.