A Fix for A Blanked Out Compass LCD

By Steve Yee:

A few weeks back, I posted an issue with my compass mirror literally "blanking out".  Well, it wasn't a blank out, but more on the line of the LED elements not getting enough power to show in daylight or even at night.  In near pitch darkness, you could make out the elements of the LED display showing up.

So, I figured I'd try a trick from the BMW side of the world, in which doing a similar method would resurrect dead pixels in their LCD display on the driver's information center (in the gauge cluster).

Note - this worked on my particular mirror, which is the stock compass mirror for a 97.5 truck.  I have no idea as to when AMG quit using this particular mirror.  It is a very common mirror, mimicing the GM compass mirror used in that same era.  This trick may work for other compass mirrors of similar type and function.

Items needed:
- 1 Can of Electronics Component cleaner.  ($3 at Auto Zone).  DO NOT GET THE VERSION THAT LUBRICATES AND CLEANS!
- Tons of rags
- A small slotted screwdriver
- A Penny (Not kidding here!)
- Ignition keys

Steps:

1) Remove the mirror from its mounting by removing the set screw.  On my particular truck, it's a torx head.  Let the unit gently dangle.
2) Get in the drivers seat, bring in all the materials, and close the door (IMPORTANT!)
3) Take the penny.  You will see some slotted round covers on the back of the mirror.  Remove the covers with the penny.  Insert the penny into the slot, and twist.  You will then see the replaceable lamps of the mirror unit.
4) Cover the dash area with rags, especially underneath the mirror area.
5) Take the Electronics component cleaner, and spray liberally and repeatedly into every orifice found on the mirror.  This will include:
- All switch seams
- The lamp cover holes that you just opened with the penny
- The Wire harness input area
- The flip switch for the mirror on the bottom (glare reducer)
- The display seam
6) Let Dry.  DO NOT GET OUT OF YOUR VEHICLE OR OPEN A DOOR!  The cleaner contains methanol and naptha or other flammable materials (to aid in quick drying).  This may ignite if you turn the lights on within the mirror itself. 
Let the cleaner dry completely for at least 5 minutes.  In the meantime, relax and enjoy the fact you own a Hummer!
7) After drying, turn the ignition on and turn the truck on.  See if the display lights up.  If not, turn the truck off, repeat.  

If after 3 times this method does not work, you truly have a dead mirror display or a dead fuse.  It is hoped that you checked the fuse before starting this exercise!

Replace all covers, caps, and reinstall the mirror after you are done.