* Fuse: A blown fuse is the most common culprit. Check your owner's manual to locate the fuse box and identify the fuse for the power mirrors. Replace it with a fuse of the same amperage.
* Wiring Issues: A broken or damaged wire in the harness leading to the mirrors is another possibility. This could be due to age, rodent damage, or accidental damage from a door being slammed too hard. This requires tracing the wiring to locate the break.
* Switch Problem: The power mirror switch itself could be faulty. Try cleaning the switch contacts with electrical contact cleaner. If that doesn't work, the switch may need replacing.
* Motor Failure: The motor inside one or both of the mirrors might have burned out. This is less common than wiring or switch issues, but possible. Replacing the mirror assembly is usually the solution.
* Power Mirror Control Module: Some Tahoes have a control module that manages the power mirrors. A fault in this module could prevent them from working. Diagnosis usually requires a scan tool.
* Grounding Problem: A poor ground connection can interrupt the electrical circuit. Check for corrosion or loose connections on the ground wires.
Troubleshooting Steps:
1. Check the fuses first. This is the easiest and quickest thing to do.
2. Inspect the switches. Try using the switches, and if they feel loose or unresponsive, that points to a switch problem.
3. Listen for any clicking sounds. When activating the switch, if you hear a faint click, it suggests a motor issue, but a lack of sound might suggest a wiring or fuse problem.
4. Manually move the mirrors. Try to adjust them manually. If they are stiff or frozen, there is likely a mechanical issue.
5. Check for obvious damage to the wiring harnesses. Look closely for any cuts or abrasions near the door hinges and the mirror assemblies.
If you've checked these and the problem persists, it's best to take your Tahoe to a qualified mechanic or an automotive electrician for diagnosis and repair. They have the tools and expertise to pinpoint the problem accurately.
