Faulty mirror folder switch (internal contact wear or contamination).; Broken or corroded wiring in the door jamb harness where the wires flex.; Loose or disconnected electrical connector at the switch or mirror motor.; Open or shorted circuit in the wiring between the switch and the body control module.; Failed mirror folding motor or actuator (though less common, it can set a circuit code if the motor draws abnormal current).; Water intrusion into the switch or connector causing corrosion and high resistance.; Body control module (BCM) internal fault (rare but possible).

DTC codes / B01xx · Airbags, seats, doors, lights and comfort systems / B0108

B0108Mirror Folder Switch Circuit

Q: What does code B0108 mean?

Mirror Folder Switch Circuit. B0108 indicates that the body control module (BCM) has detected an abnormal condition in the electrical circuit for the mirror folder switch, which is the switch used to fold or unfold the exterior mirrors. The computer monitors voltage or current on the switch signal circuit and sets this code when the readings fall outside the expected range, typically indicating an open, short, or excessive resistance in the wiring or switch.

B0108 indicates that the body control module (BCM) has detected an abnormal condition in the electrical circuit for the mirror folder switch, which is the switch used to fold or unfold the exterior mirrors. The computer monitors voltage or current on the switch signal circuit and sets this code when the readings fall outside the expected range, typically indicating an open, short, or excessive resistance in the wiring or switch.

SystemBody

Code typeGeneric (all makes)

SeverityLow

Fix difficultyIntermediate

AreaAirbags, seats, doors, lights and comfort systems

Symptoms you may notice

The power folding mirror function does not work when the switch is pressed.
The mirror may be stuck in the folded or unfolded position.
The mirror folder switch may feel loose or unresponsive.
Often no symptoms besides the warning light, especially if the mirror was rarely used.
In some vehicles, other mirror adjustments (like tilt or turn signal) may also be affected if they share the same switch module.

Common causes, most likely first

Faulty mirror folder switch (internal contact wear or contamination).
Broken or corroded wiring in the door jamb harness where the wires flex.
Loose or disconnected electrical connector at the switch or mirror motor.
Open or shorted circuit in the wiring between the switch and the body control module.
Failed mirror folding motor or actuator (though less common, it can set a circuit code if the motor draws abnormal current).
Water intrusion into the switch or connector causing corrosion and high resistance.
Body control module (BCM) internal fault (rare but possible).

How to diagnose and fix it

Use a scan tool to confirm B0108 is current and check for any related body codes in the BCM.
Inspect the mirror folder switch for physical damage, contamination, or loose mounting, and test its continuity with a multimeter while operating it.
Check the wiring harness at the door jamb for chafed, broken, or corroded wires, and repair as needed.
Disconnect the switch and mirror motor connectors, then measure resistance and voltage on the signal circuit to isolate an open or short.
Test the mirror folding motor directly by applying power and ground to confirm it operates smoothly and does not bind.
If all wiring and components test good, suspect the BCM and perform a voltage drop test on its ground and power feeds before replacement.

Mirror folder switch circuit pitfalls

A common oversight is replacing the switch without checking the door jamb harness, where repeated flexing often breaks the wires and sets this code.
The code can be set by a mirror motor that is drawing excessive current due to internal binding, even though the switch and wiring are fine.
On some vehicles, the mirror folder switch shares a ground with other door functions, so a bad ground can trigger B0108 along with other unrelated symptoms.
After repairing the circuit, the code may remain stored until the BCM sees a complete cycle of the switch, so clear codes and operate the switch several times to verify the fix.
Water intrusion from a clogged sunroof drain or door seal can corrode the switch connector and cause intermittent B0108 without any visible damage to the switch itself.

Can I keep driving with B0108?

The vehicle remains safe to drive because the mirror folder circuit does not affect steering, braking, or lighting, but you should avoid using the folding function until repaired to prevent further damage. If the mirrors are stuck in a position that obstructs your view, manually adjust them or fold them by hand if possible before driving.

Tools that help

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Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.