Mirrors: heating, folding, and adjustment that stopped working

A modern door mirror is three or four separate systems in one housing: the adjustment motors, the heater, the folding motor, and sometimes an indicator repeater, a puddle light, and a camera. They fail independently, and that is the main clue when searching.

The search logic

One function out of four fails — the problem is in that function: a motor, a heating element, its own circuit.

Nothing works in that mirror — supply or wiring to it.

Nothing works in that door — including the window and lock — that is the wiring in the loom between body and door; covered in the electric windows article.

Neither mirror works — fuse, switch, or module.

That sequence saves the most time.

Heating

One mirror does not heat — a broken element or its contact. The repair usually means replacing the glass unit rather than the whole housing.

Neither heats — fuse, relay, or switch. Mirror and rear screen heating are often one circuit; covered in the heated screen article.

A clue: if the rear screen fails to heat alongside the mirrors, look for one shared circuit rather than three faults.

Folding

It buzzes but does not fold — a worn mechanism or ice. The most common winter failure.

The most frequent cause of damage: folding the mirror by hand on a car with power folding. The gear teeth strip and the motor then turns with no result.

The rule: if the power function exists, use it rather than your hand.

Another cause: the mirror was folded, the car froze, and the motor tries to unfold a frozen mirror. In winter let it thaw.

Adjustment

No movement in one direction — one of the two motors or its circuit.

Jerky movement — the mechanism or the supply.

Neither mirror adjusts — the joystick or the module.

Wiring in the door loom

The cause that explains most “inexplicable” cases.

The harness passes from body to door through a rubber boot. There the wires fatigue after thousands of opening cycles.

The sign: everything in that door works intermittently, depending on door position. Mirror, window, lock, and speaker together.

The repair: restoring the conductors in the loom; standard work.

What diagnostics shows

Door module codes — per actuator: open circuit, short, position error.

Switch states in live data.

Voltage — during a sag the actuators move sluggishly, which looks like wear; covered in the parasitic drain article.

Camera codes — on mirrors with a surround-view camera; calibration may be needed after replacement.

In short

• One function failing is that function; nothing in the door means the loom.
• Mirror heating often shares a circuit with the rear screen.
• Folding a power mirror by hand is the main cause of its failure.
• In winter do not try to power-unfold a frozen mirror.
• The door module names the specific actuator in the code.

Download the app — door module codes and voltage are read with an ELM327 adapter over Bluetooth SPP on Android.