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How to: Rearview Mirror Upgrade

110114 Views 195 Replies 53 Participants Last post by  GeorgiaBoy
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A 355nation How To presented by
rshadd, comdrop9073

Project Name
How To upgrade your rearview mirror

Project Description
Upgrading your manual inside rearview mirror with auto-dimming, compass and outside temperature display.

Skill Level

Project Vehicle
Make: Chevrolet
Model: Colorado
Year: 2009
Engine: 3.7L
Power windows: Yes
Sun Roof: No

Tools Needed
  • Safety Razor or Utility Knife
  • Pliers
  • Torx T-20
  • Wire Strippers / Crimpers

Parts Needed
  • Auto Dimming RearView Mirror, with OnStar, Compass and Outside Temp (GM Part# 15269045)
    (You should be able to find one on Ebay or your local salvage yard for about $25-$100)

    Note: The OEM mirror is manufactured by Gentex. The mirror used in this how to is a Gentex 511. You can find good deals on eBay. Just search for a Gentex
    The mirror was purchased off ebay from the seller:
    He included the mirror, 16 pin plug and wires (if needed) and temp sensor with plug and wires for $110 shipped. Much cheaper than ordering through GM.
  • Ambient Air Temperature Sensor, GM#25775833 ($7)

  • Small Spool of Two Conductor (zip cord) Wire (14-16AWG) ($20)

  • Quick Splice Connectors with Male Disconnectors. They're available at Radio Shack in a 3-Pack (Model: 64878006D,MDFNY1-250 | Catalog #: 64-037). ($2.19)

  • 1/4" or 1/2" Split Cable Tubing. Radio Shack Model: 278-1624 | Catalog #: 278-1624 ($6)

  • Small Zip Ties - (10) should be plenty
  • Black Electrical Tape

Project Time
1 hour or less

Project Cost

Installation Procedures

  1. Remove your existing inside rearview mirror and replace it with your new auto-dimming mirror.

    • Remove the inside rearview mirror cover, if equipped
    • Disconnect the electrical connector, if equipped.
    • Adjust the mirror to the full upward position.
    • Loosen the set screw (torx) located at the base of the mirror.
    • Slide the mirror upward off of the rearview mirror button.
    • Simply reverse this procedure to re-install your new mirror.

  2. Remove the grill to access to ambient air sensor location. Refer to CodeRed's grill removal how-to for help.

  3. On the center bar off the core support you will see a hole. This is where the Ambient Air Temp Sensor will be installed.

  4. The Ambient Air Temperature Sensor is inserted from behind into the hole in the center support.

    Once installed it'll look like this:

  5. Run your two wires from the temperature sensor up behind the air box, make sure to secure the wires along the way with wire loom and zip ties (or fastener of your choice).

  6. Remove the air box and locate the plug. (I have a K&N which makes it easier to get to, the OEM airbox will need to be removed)

    (I don't know the name for this plug, but the wires for the foglights, horn and looks to be Airbag sensors?? two along the back side of the core support pass through it.

    This plug can be removed from the body using a trim removal tool. In this case Quick Splice Connectors were used to tap into the wires.

  7. The wires you need to tap are the bottom two in the front row when the barbed pin is facing towards you.

    Photo Credit: CUZICAN

Electrical Schematics and Connector Pinouts

Note: Depending on the year of your truck, some the wire colors are different, but the pin locations are still the same.

For the trucks with a 7 pin harness: (this is the harness that plugs into the back of the mirror)
PIN 1 PINK POWER +12 volts
Note: Pin 3 is to be connected to the backup lights to turn off the auto dim feature in reverse. If you intend not to use this feature connect the LT GRN wire to chassis ground. If this pin is floating the auto dim will not work properly
PIN 1 = Grey = not used
PIN 2 = Bare = Microphone
PIN 3 = "Passenger Air Bag on" notification (some GM trucks - ground pin to activate)
PIN 4 = "Passenger Air Bag off" notification
PIN 5 = auto day/night signal from LH outside mirror (use w/ pin 16)
PIN 6 = Brown = Temp probe connection
PIN 7 = Green/Black = Temp probe connection
PIN 8 = Black = Ground (Common to Pin 9)
PIN 9 = Light Green = Reverse Dim Inhibit
PIN 10 = Gray = Microphone
PIN 11 = Dark Green/White = keypad signal (out)
PIN 12 = Light Green = keypad +5v supply (in)
PIN 13 = Yellow = +12V switched (ignition)
PIN 14 = Yellow/Black = Green LED signal
PIN 15 = Brown/White = Red LED signal (apply 12v to light LED)
PIN 16 = day/night signal to LH outside mirror
The 12volt has a lot of information on the Gentex mirrors.
Gentex mirror wiring diagram

If you are not getting a good connection to the sensor or the wires are backward the mirror will display OC (Open Circuit):

Completed pictures:
Gentex 511 Auto Dimming Mirror(top), Original manual Mirror (bottom):

Auto Dimming Mirror:

Compass and Outside Air Temperature

Auto Dimming Mirror. Dimmed:

Compass Operation

or depending on the mirror, press
once to turn the display on or off.

Compass Calibration
The compass may need calibration if:
  • CAL is displayed while driving in the vehicle.

  • After approximately five seconds, the display does not show a compass heading, N for North, for example, there may be a strong magnetic field interfering with the compass. Interference can be caused by a magnetic antenna mount, magnetic note pad holder, or a similar magnetic item.

  • The compass does not display the correct heading and the compass zone variance is set correctly.

To calibrate, CAL must be displayed in the mirror compass windows. If CAL is not displayed, press and hold
for several seconds or until CAL is displayed.

The compass can be calibrated by driving the vehicle in circles at 5 mph (8 km/h) or less until the display reads a direction.

Compass Variance
The mirror is set to zone eight. If you do not live in zone eight or drive out of the area, the compass variance needs to be changed to the appropriate zone.

To adjust for compass variance:

  1. Find the current location and variance zone number on the following zone map.

  2. Press and hold
    until Z and/or a zone number displays.

  3. Press
    repeatedly until the new zone number displays. After you stop pressing the button, the display shows a compass direction within a few seconds.

Temperature Display
(On/Off): Press
or depending on the mirror, press
to turn the display on or off.

To adjust between Fahrenheit and Celsius:

  1. Press and hold
    for a few seconds. The current unit of measure (F or C) flashes.

  2. Press
    again and release to change the unit of measure. Wait several seconds and the compass/temperature display returns with the selected unit of measure.

It is normal under certain conditions for the temperature update to be delayed. If an incorrect temperature displays for an extended period, see your dealer/retailer.

Thanks to Dave for the great pics.
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Burn's how-to on this mod was missing all it's pics, so I created a new one.
Is this type of mirror equipped with maplights?
Is this type of mirror equipped with maplights?
No maps lights in this version. I believe the 2012+ Escalades, Tahoes, etc. offer that, but they're like $400 and hard to find used at a reasonable price. Heck, some of the newer mirrors even offer a built-in LCD screen for a backup camera.
very detailed Rich nice job I'm gonna have to do this myself
Back in 2007 when I got my new Canyon SLE 3.7 4x4 it came with regular mirror with map lights. I wanted the bench seat but you could only get it with the temperature/compass/map lights if you ordered the leather bucket seats. Which made no sense. What the hell did the seats matter? Any way I don't remember which mirror it is but I bought a brand new one for $120.00 off e-bay that had the temperature/compass/map lights and it was simple to put on. My harness plugged right into the back of mirror and I spliced down on the fender by the air cleaner for the temperature probe and at that time you clipped the probe on that center bar in front of the radiator. And Its always worked perfectly.
Thanks for re-doing the how-to Rich, this needed to be done. This is still the best money I've spent on my truck.
I'm waiting for my sensor and harness to arrive. Will this tap work on a truck with no fogs, or can I run the wire up to the back of the mirror while the headliners's out?

Great how to by the way!!!
The part about trucks with no fogs has yet to be confirmed, it is still a rumor until some can prove it or dis-prove it. Take a look at your harness on the pass inner fender and see if those two wires are there and on the plug at the back of the mirror.
The part about trucks with no fogs has yet to be confirmed, it is still a rumor until some can prove it or dis-prove it. Take a look at your harness on the pass inner fender and see if those two wires are there and on the plug at the back of the mirror.

My temp is showing the "OC" code. The wires, (Yellow and green with white stripe) are coming out of the harness plugged into the mirror. I was gonna run the wires off the sensor into the cab and tie them into the harness behind the mirror...
No need to go that far with them, if the wires are on the pass inner fender. Also my wire colors were green and green with white stripe.
You have the OC (open circuit) code because you haven't connected the ambient temp sensor.
You have the OC (open circuit) code because you haven't connected the ambient temp sensor.
Got that Rich, Just trying to narrow down where I make the connection. (No fogs)

Wed's, I'll be working on that fix... I'll have both the sensor and harness tomorrow.
First place to look is the harness on the inner fender, if it's not there then you'll probably have to go to the mirror, but check the harness first, if the wires you need are there, then tap in there.
Hi All,

I have a 2005 gmc canyon 3.5L 4x4 with the rear view mirror that has the maplights (no Onstar, etc). I am looking for a Rearview mirror with the auto dimming, temp, compass & maplights (Don't care about Onstar). My problem is that I can't seem to find which models have those features that will work for my truck. Is there any recommendations out there? I see Gentex was used here but when I goto I can't find anything or anyone who sells them let alone info of what models they have would work with my truck.

Also will I require any special wiring other then the splice by the airbox?

Thanks everyone.


So my current mirror has only two wires (for the map lights). Do I need to run the two wires from the temp sensor all the way into the plug for the new mirror? or will the wiring still be there under the airbox? I was thinking of getting the donnelly 19697 since It seems like what would have came with our trucks. Not really a fan of the temp n compass being in the mirror pane. Problem is trying to find one.. Not much for used parts in the junkyards up in Ontario, Canada... Hope someone has an idea and can help me out.

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Where can I find a temp sensor with the pigtails/plug all the ones I found are just the sensor.
I need the mirror with the map lights and all the other junk. what truck has all that stuff
with the rectangle plug ?
Where can I find a temp sensor with the pigtails/plug all the ones I found are just the sensor.
Here ya go.

Gentex Donnelly Rear View Mirror Temperature Sensor Probe Harness Temp Sencor | eBay

I need the mirror with the map lights and all the other junk. what truck has all that stuff
with the rectangle plug ?
What do you mean by all the other junk? Auto-dim? Temp? Compass?
Finding one that's dimming, temp, and compass is easy, it's when you add map lights to that, that they get hard to find.

This one looks to have everything but the temp on it.|Model:HHR&hash=item53ec2def72&vxp=mtr
Auto dim, compass, temp and map lights? They are hard to come buy and pretty expensive when you do. I believe some Escalade's came with them.
I still need a plug then I'm good to go :cry:
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