1994 GMC wiring diagram for inside mirror for outside temp. and compass 3pin satup

There is help in the link. The general consensus is if neither work, you need a new mirror.

https://www.google.com/search?q=2015+GMC+ACADIA.+Compass+and+temperature+won%27t+work+in+my+rear+view+mirror

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Does the compass work when the temperature goes out? If the compass still works then chances are that the ambient temp sensor is defective. Also, could be wiring to the sensor. If the compass goes out with the temperature then chances are the mirror itself is defective. Cheapest most common problem is the ambient temp sensor. It's behind the grill by the condenser at the front of the vehicle.

check your fuse box if that checks out ok than you need to replace your rear view mirror.

go with a higher watt

Temperature Display
The inside rearview mirror supplies a 5 volt signal circuit and low reference circuit to the ambient air temperature sensor. The inside rearview mirror monitors and records the voltage on the signal circuit of the ambient air temperature sensor. The inside rearview mirror uses this recorded voltage to display the temperature on the temperature display portion of the compass/temperature display. The temperature display will show "ICE" when the ignition is first turned on and the current temperature is 3°C (37°F) or below. The display will toggle between "ICE" and the actual outside temperature for approximately 4 minutes.
The mirror will display "OC" if the mirror senses a temperature of less than -40°C (-40°F).
the mirror will display a "SC" if the mirror senses a temperature of greater than 112°C (143°F).



Replace the inside rearview mirror with compass. Refer to Inside Rearview Mirror Replacement .

here's 1996, all I have. Please rate.

Mirror, Power — Outside Rear View NOTE: This procedure applies to both RH and LH power outside rear view mirrors.

Removal

1. Remove the front door trim panel (23942). Refer to Section 01-05 for the removal procedure.
   

1. Remove the two outside rear view mirror inside mounting hole cover screws and the outside rear view mirror mounting hole cover (17K709) from the front door (20124).
   
   
   
   
   

1. Remove the wire clip.
   

1. Disconnect the power outside rear view mirror electrical connector.
   
   
   
   
   

1. Remove the three power outside rear view mirror bolts and the power outside rear view mirror.
   
   
   
   
   

Installation
To install, reverse the removal procedure. Tighten the three power outside rear view mirror bolts to 3-4 Nm (27-35 lb-in). Glass, Outside Mirror
Removal and Installation
Refer to the glass replacement procedures in Manual Mirror for power outside rear view mirror glass (17K707) Trim Cover
Removal

1. Remove the front door trim panel. Refer to Section 01-05 for the removal procedure.
   

1. Remove the two outside rear view mirror inside mounting hole cover screws.
   
   
   Remove the outside rear view mirror mounting hole cover.

Installation
To install, reverse the removal procedure. Mirror Control
Removal

1. Use a small flat-blade screwdriver to pry the power outside rear view mirror control switch from the instrument panel (04320).
   
   
   

Check the connector that plugs into the back of the mirror and make sure it is pushed in all the way. If that is not it, look carefully at the wires going into the connector. I had one that broke off. I had to pull the pin out of the connector and re crimp it onto the wire.

you could always try unplugging the battery for about ten minutes to see if that resets it. make sure you have the code for the stereo first if it requires one.

Yes. Look in the Fuse Panel inside the Truck. Use a Good Maglight or LED Flashlight and Hold it Behind the Fuses to see the Blown Ones. It is usually in an AUX Outlet. Also check thr Fuse Relay Box under the Hood for a Blown Fuse using the Same Method. See if there is a Relay for this also. If so, Replace it. Let me know if you need any more Help! Please Rate my Response, I need all the Help That I can Get!

Running wires from external sensors is going to be a difficult job because you have to drop the headliner and the left A post cover for access to the wires. There are manuals available at auto parts stores that have diagrams, but you need to be sure that it covers the wiring for the new mirror.