DIY Network

Truck Accessories: Electronic Compass-Mirror From "Weekend Mechanic" episode WKM-310

	Bruce Bonebrake replaces the rearview mirror on a GMC truck with an electronic mirror that automatically dims.
	This mirror also features digital readouts of compass direction and outside temperature.

In this segment of DIY's Weekend Mechanic, host Bruce Bonebrake replaces the rearview mirror on a GMC truck with an electronic mirror that automatically dims and features outside-temperature and compass digital readouts. An electronic mirror like the one installed in this segment costs around $200.

Materials:

In addition to standard auto-mechanic's tools (wrenches, ratchets, extenders, screwdrivers, nut-drivers, torque wrench, etc.), some of the specialty tools that will be needed for the projects in this episode include air chuck, tire gauge and valve tool, wire-strippers and wire cutters, air wrench and safety glasses. An air-compressor and set of pneumatic tools will is optional, but may be very helpful for this project.

DIY Difficulty Rating for the Project: The projects featured in this episode are all fairly straightforward, and should be no problem for experienced automotive do-it-yourselfers. Overall, we gave the projects a difficulty rating of 2 on a 5-point intermediate-level scale. It took us about 12 hours to finish this job. Depending on the nature of your upgrades and type of vehicle, your work time could vary. Allow yourself a full weekend to complete these projects properly.

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Electronic Mirror Upgrade

• The new mirror assembly mounts on the tab as the factory mirror. The compass sensor is actually built into the mirror's mounting bracket (figure A).

• To provide the temperature reading, a temperature probe (figure B) is mounted behind the front bumper.

  Figure A

  Figure B

  
  

• The wiring harness (figure C) plugs into the mirror on one end and the temperature sensor on the other. The harness comes with a ground, power-supply and inline fuse-holder.

  Note: Any extensions to this wiring must be made with the same gauge wire as the

• Begin the installation by loosening the screw that holds the factory mirror on the mount (figure D) and removing the mirror. Once the mirror is off, check it to be make sure that it's secure.

• Snap the wiring connection onto the new mirror, then install the mirror on the existing windshield mount.

  Figure C

  Figure D

  
  

• To run the wiring for the electronic mirror, remove the sun visor and roof-pillar trim, and loosen the headliner. Tuck the harness up under the headliner and run it toward the roof pillar (figure E).

• Lace the wiring harness down the roof pillar (figure F) and route it toward the fuse box. These wires will be connected later after running the temperature-sensor wire.

  Figure E

  Figure F

  
  

• Reinstall the pillar trim-piece, snap the headliner back in place and reinstall the sun visor (figure G).

• The temperature-sensor wire is then passed through a hole in the firewall and covered with a wire loom to protect it.

• Next, connect the wire to the cable from the temperature sensor (figure H). This particular connection simply plugs in and does not need taping.

  Figure G

  Figure H

  
  

  	Figure I
  	Figure J

• Feed the temperature-sensor cable down, past the engine and mount it in a convenient location under the truck body (figure I). Mount the sensor outside the truck body, but in an area where it is protected from being hit by road debris.

• Following the manufacturer's wiring instructions, connect the ground-wire from the mirror harness to the fuse box, and connect the red power-line (with inline fuse) to the fuse box (figure J).

• Important: Test the fuse-box circuits with a volt meter or test light before wiring.

• Reinstall the fuse-box cover. The mirror is now ready to use.

• When the ignition is turned on, the temperature readout should appear. After a short calibration, the compass direction should appear as well.

  Tip: A good way to help calibrate the compass for best accuracy is to find an empty parking lot, and drive around in circles (clockwise, then counterclockwise) a few times.
  

Important: Included in this segment are the steps in this automotive procedure as shown in the episode. These steps are general guidelines that are applicable to most vehicles. With any particular vehicle, there may be procedures, specifications, settings, tolerances, components, etc. that are specific to that vehicle. There are also variations according to the type and brand of repair-kit you select. Always consult your vehicle's service manual when undertaking significant automotive repairs, and read and follow the manufacturer's directions and precautions that come with your kit or replacement parts.

Safety Alert: As a standard safety precaution, always disconnect the vehicle's negative battery cable before you begin work on any electrical or mechanical components.

RESOURCES :

The Complete Idiot's Guide to Trouble-Free Car Care
Author: Dan Ramsey
ISBN: 0028635833
Alpha Books

Auto Repair for Dummies
Author: Deanna Sclar
ISBN: 0764550896