Gmc Sierra Power Folding Mirrors Not Working? Fix It Fast

GMC Sierra power folding mirrors not working is most commonly caused by a faulty mirror fold motor, blown fuse, or wiring issues in the door harness.

Start by checking fuse #10 in the underhood fuse box. Then, test the switch and motors with a multimeter before replacing expensive parts.

What causes power folding mirrors to stop working on GMC Sierra?

The power folding mirrors on GMC Sierra trucks fail due to several common issues rooted in daily use and OEM design flaws. Electrical gremlins like corroded connectors and worn motors top the list.

These are often misdiagnosed by dealers as full mirror assembly replacements costing over $800. Independent shops frequently overlook harness chafing, which leads to repeat failures over time.

These problems spike after 5-7 years or 80,000 miles, especially on 2014-2020 models. Water intrusion from poor door seals accelerates corrosion, while heavy towing puts extra stress on the internal motors.

Top 5 Most Common Causes

• ➤ Faulty fold motor: The small DC motor inside each mirror wears out from repeated folding cycles, common on Sierras used for trailering.
• ➤ Blown fuse or relay: Fuse #10 (mirror circuit) blows from shorts, while the fold relay in the passenger kick panel can stick.
• ➤ Wiring harness damage: Chafed wires in the door hinge area from constant flexing break the circuit to the motors.
• ➤ Defective mirror control switch: The door switch module fails internally, failing to send the signal to fold.
• ➤ Body Control Module (BCM) glitch: Software bugs or water damage in the BCM interrupt fold commands, especially on 1500 series.

Model-Specific Weaknesses

2014-2018 GMC Sierra 1500 and 2500 models suffer most from motor failures due to cheaper OEM motors. Newer 2019+ Sierras with updated harnesses see fewer issues but still battle BCM glitches after recalls.

Heavy-duty 3500HD variants add vibration-induced wire breaks from off-road abuse. Understanding these root causes saves owners from unnecessary dealer quotes pushing extended warranties.

How to diagnose GMC Sierra power folding mirrors not folding?

Diagnose by systematically testing power, signals, and motors using basic tools. Most owners can fix it without a scan tool if they follow a logical sequence.

Dealers often skip fuse checks and jump to $1,200 mirror swaps. Follow this sequence to pinpoint the fault in under 30 minutes.

Tools Needed for Diagnosis

• Digital multimeter (under $20)
• Test light or power probe
• Torx bits (T20-T30) and trim removal tools
• 12V test battery or jumper wires
• Socket set for fuse box access

Step-by-Step Diagnostic Procedure

1. Verify basic power: Turn key to ON and press the fold button. Listen for a relay click in the passenger footwell and any mirror motor hum.
2. Check fuses and relays: Pull #10 (15A mirror fuse) and #42 (BCM) in the underhood box. Swap the fold relay (position R10) with the horn relay to test.
3. Test door switch: Remove the door panel and unplug the switch harness. Probe pins 4 (ground) and 6 (signal) for 12V when pressed.
4. Inspect wiring: Peel back the rubber boot at the door hinge. Look for chafed insulation or broken wires that break the circuit.
5. Bench test motors: Remove the mirror and apply 12V directly to the motor wires. Jerky or no movement confirms a dead motor.

Symptom	Quick Test	Probable Cause
No relay click	Check fuse #10	Blown fuse/relay
Click but no movement	Probe mirror harness	Wiring or motor
One mirror works	Test door switch	Bad switch or harness
Intermittent folding	Door boot inspection	Chafed wires

GMC Sierra power folding mirrors fuse location and reset

The main fuse for power folding mirrors is #10 (15A) in the underhood fuse center. A simple pull-and-reseat often resets sticky connections; no full reset button exists like on some other brands.

Fuse Box Locations by Model Year

• 2007-2013 Sierra: Fuse #10 underhood, relay R9 in cab fuse box behind glovebox.
• 2014-2018 Sierra 1500/2500: Underhood #10 (15A), BCM relay R10 passenger kick.
• 2019+ Sierra: Integrated fuse block underhood, #57 (mirror module) + app-based reset.

How to Check and Replace

1. Open the hood and locate the black fuse box cover near the battery.
2. Pull the #10 fuse and inspect for a melted or blown element.
3. Test the fuse with a multimeter (0 ohms is good).
4. Cycle the key OFF and ON to test the fold function.

Pro tip: Use Bussmann ceramic fuses for better short protection—they last longer than OEM plastic ones prone to nuisance blows.

How to fix GMC Sierra power folding mirror motors DIY

Replace the fold motor yourself for $50-80 per side versus $400 in dealer labor. Access requires mirror glass removal, not a full assembly swap.

Parts Needed

• OEM or aftermarket fold motor (Dorman 344-582 fits 2014+)
• Dielectric grease
• Torx T20, pliers, and flathead screwdriver

Model-Year Specific Fixes

For 2014-2018 Sierra 1500/2500:

1. Pop mirror glass up from bottom clips and unplug harnesses.
2. Remove 3 Torx screws holding the motor cover.
3. Disconnect motor wires and twist the old motor counterclockwise to remove.
4. Reassemble with grease on the gears and test before full install.

GMC Sierra power folding mirrors wiring diagram and repair

Wiring faults often hide in the door harness boot. Diagrams show the violet/white wire (fold signal) and black (ground) as common hotspots for failure.

Wire Color	Function	Pin at Mirror
Violet/White	Fold signal	Pin 3
Black	Ground	Pin 1
Orange	12V constant	Pin 2

FAQs

Why do GMC Sierra mirrors unfold themselves randomly?

This stems from BCM glitches or sticky relays detecting phantom signals. Clean relay contacts or flash a BCM update via a dealer tool.

Can I manually fold GMC Sierra mirrors if power fails?

Yes, press firmly on the glass edge toward the hinge until it stops. Avoid forcing too hard to prevent stripping the internal motor gears.

In summary, most GMC Sierra power folding mirror issues trace to preventable electrical faults you can diagnose DIY. Skip dealer overquotes by starting with fuses and wiring—your truck will run like new without the $1,000 hit.