Picked up an auto dim mirror out of a 94 F150.

Looking for a wiring diagram for the 3 wire plug in.

Any help would be appreciated.

 

I'm gonna bump ya back to the top before you drop off the first page.

I didn't know a 94 had such a mirror and my book makes no mention of it whatsoever.

Best bets probably gonna be Subford, if anyone can answer your question here I'm fairly sure he can.

 

Appreciate the bump. Pulled this out of a 94 F150 XLt Super cab.
Wiring is.......Blk/Pink.........Blk........Wht./Purple

Also pulled an identical unit out of a 96 Dodge 1/2 ton.

 

The only trucks of our era that i have seen with that mirror are Bronco's. Was the truck an EB?

 

Wiring is.......Blk/Pink.........Blk........Wht./Purple

Just the three?

Might be able to answer your question if you post what exactly the mirror can do, must be more then auto dimming mirror to have a third wire?

Lets assume the black is a ground for the moment, would stand to reason (sometimes that's of no help though!!).

You said it has the auto dim feature, ok that would need power? That be one of the Blk/Pink or Wht./Purple wires and the black.

What else does it do? A button to turn on/off the auto head lights?

If so one is a switched circuit for a relay? testing each combination for continuity on/off while activating that switch should give you the answer. One of the Blk/Pink or Wht./Purple wires with the black wire for example.

Third wire for a temp sensor perhaps?

Opening the mirror case up might also give you more clues as to what wire goes to/does what?

 

My truck didn't have the mirror when I bought it but I have the pigtail hanging down for it. It is an EB too though and I've been on the lookout for one to put it back in the truck.

 

Your wires at the pigtail the same color as his?

If so maybe you could test your pigtails circuits for power and continuity to ground, that would or should get em two out of three?

 

I'll have to go out and take a look. I'll let you know!

Thinking about it in my mind though, (only speculation) one is the ground. One might come from the headlight switch to dim the mirror manually. The last one might have constant power, hooked in series within the mirror to a light sensor so when someone comes up behind you with their brights on it will dim the mirror automatically. I'm not sure though as it's been a long time since i've seen the factory mirror and don't know where they would have the sensor. They might have a hole in the reflective coating in the corner or something so light can pass through. Again only speculation. lol.

 

hole in the reflective coating in the corner or something so light can pass through

Yea exactly, that's the way the wife's last couple cars mirrors do it.

 

I have already sent him a wiring diagram of the circuit.

 

Subford strikes with the good info again! Just out of curiosity, was I close to being right with the wires? I need to find me one of those mirrors and hook it up. The last one I seen at the junkyard was out of a 95 EB bronco but it was laying in a puddle on the floorboard and didn't want to chance it. lol.

 

Here is the diagram:

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Intersting. From what I can see, it's sending power to the mirror when you engage Reverse. I wonder if powering the mirror is what makes it more reflective because I would assume that you would want full reflectivity when in reverse. The other lead is hot, probably going through the light sensor. If the same rules would apply to it, I wonder if it gets dim when you turn the power to the truck off. It might also be so subtle that you would never notice it in the daylight. I guess i'll just have to get one and see. Thanks Bill!

 

Thanks again Subford. There is a small dot in the center of the glass....also an on/off switch on the bottom of the mirror casing.

 

Mirror, Inside, Electronic Day/Night, F-Series and Bronco

The electronic day/night mirror changes from the normal state to the non-glare state when glare reaches the inside rear view mirror (17700). This inside rear view mirror mainly functions at night, with limited function at dusk or dawn.

From the non-glare state, the inside rear view mirror will return to the normal state after a short delay. The delay starts when glare goes away, and prevents excessive changing of the inside rear view mirror as traffic moves behind and around the vehicle, or on rolling hills and curves.

The electronic mirror also measures the brightness of the light in front of the vehicle. It automatically makes a correction in the glare state. The automatic function of the inside rear view mirror may be turned off by pushing the switch to the OFF position. It may be turned off in either the normal or non-glare state.


There are two light sensors (photocells) in the inside rear view mirror. The sensor that detects rear glare is located inside a window in the center of the inside rear view mirror. The second light sensor, which determines outside light level, is located on the backside of the inside rear view mirror case.

The inside rear view mirror automatically locks in the normal state whenever the vehicle is placed in REVERSE. This feature makes sure the view in the inside rear view mirror is clear and bright when backing up.


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