Yellow Outside Rearview Mirror 98 JGC ltd

My wife's 98 JGC just developed a jaundiced driver's side rear view mirror. Since we were on a trip, we had a chance to fiddle around with things (and even read the manual!) and discovered that this mirror is supposed to autodim along with the autodim inside rearview mirror. That one has a clear button on the underside which according to the manual is supposed to light up when in the autodim mode - only our button doesn't light, but when in the pushed up position, both mirrors get pretty dark, and then when moved to the down position, the mirrors very slowly clear. The dashboard lights are acting up as well. Does anyone have a theory about what's up? I suspect something went wrong electrically somewhere, and it's messing up the supply voltage to these circuits, or something went wrong with something in the autodim (like the outside mirror died)and that's what's messing other things up. Is it possible this is just a fuse somewhere? Has anyone else ever seen the outside rear view suddenly go quite yellow in color? Since we were on the road, we noticed several other cars with decidedly yellow mirrors. Thanks for any suggestions..

Rick

Reply to
Rick Cunningham
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I work on GM cars and trucks for a living, but the circuits are likely pretty similar. The electrochromatic fluid in your mirrors reacts to voltage and darkens the mirror. One of the by-products of this system is that the LS mirror will start to turn that particular color of yellow after awhile. As far as the system operation goes, there is a light sensor, usually integral to the inside rear view mirror, that picks up light that is directed from behind, such as when a car is behind you at night. This photocell transmits the voltage to the little microcircuit inside the mirror, and then the mirror determines when to turn the LS mirror on and off in conjunction with the inside mirror. They should work in tandem.

If the mirrors are darkening at all times, you likely have a faulty photocell, and hence a faulty mirror. On GM vehicles, the inside mirror has a little sensor right on the glass portion of the mirror, you can see it. If your Jeep is similarly equipped, then I would wager that this is your culprit. Perhaps someone else in the group has a better resource for the actual location of this photocell. At any rate, double check what I am telling you with the parts guy at the dealership before you buy anything.

Jerry

Reply to
belowme

Approximately 11/16/03 17:08, Rick Cunningham uttered for posterity:

There should be a green LED in the button on your rear mirror for the autodim. The wiring to the mirror sorta sucks in quality, I just removed the connector, removed the wrapping, cleaned up the wiring and then put a Fry's tube on it. Kinda not good news if the LED don't light, as means something is wrong inside the mirror. It ain't bright, but you can see it by simply shielding the little button with your mitts.

The outside mirror has a defroster in it that has been known to stick on, and cook the mirror. Comes on with rear defogger, feed is from the rear defogger relay. The glass is replaceable if you can get a dealer to get you only that part.

On the rear view mirror, pop the little tab and pull off the wiring. The black wire should have a good ground on it. If not, it goes foofoo or worse and the rest of this test is of no use.

Then turn on ignition, put transmission in Reverse with Park brake on. Should have full battery voltage on brown/light green wire. The purpose of this wire is to inhibit the dim function when in Reverse. If you don't get full battery voltage, you probably have bad wiring to the backup lamps. Fun. The voltage should change when you move the Xmission to Neutral or Drive with key on.

Reply to
Lon Stowell

Approximately 11/16/03 17:51, belowme uttered for posterity:

The cell is on the mirror. The mirror should lighten and darken as the Xmission is switched to Reverse [inhibit darken] or if the light is blocked in drive or neutral with key on, presuming a bad wiring in the notorious backup lights isn't buggering up the mirrors.

There are two sensors. The forward facing one checks for ambient light, the rear for the dimming. The forward sensor is off center on the forward face of the mirror across from the plug. To test, completely block that sensor with a couple layers of black electrical tape. Then shine a light into the rear facing sensor [located at the top center of the mirror face] and the mirror should darken. Shift to Reverse and should lighten. Repeat until you get bored.

Reply to
Lon Stowell

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