Place the multimeter probes on the two spade terminals of the mirror glass to test its resistance.
A functional heating grid should read between 10 to 30 Ohms .
Disconnect the two wires directly from the back of the mirror glass. Switch your digital multimeter to the Ohms ( Ωcap omega
If you register , power is not reaching the mirror head. Proceed to Step 5. Step 5: Check the Door Hinge Wiring Harness ford b166a60
: A "Trailer Lighting Fault" or "Check Trailer Lamps" message may appear on the instrument cluster. Potential Causes
Info on some DTC errors, read with FORScan - Ford Focus Club
If the wiring appears intact and the fuses are good, the problem may be within the door control module itself. Diagnostics for complex body control issues can sometimes require specialized equipment to scan the DDM/PDM directly. Place the multimeter probes on the two spade
is a Diagnostic Trouble Code (DTC) used in Ford vehicles to indicate an issue with the Heated Mirror Circuit MFC Auction Code Definition DTC B166A: Heated Mirror Circuit. Sub-fault :60: Typically indicates an Event Information Signal Plausibility Failure , often manifesting as an "Interrupt" in the circuit. MFC Auction Common Symptoms
Conquer the Mess: A Deep Dive into Ford’s B166A60 All-Weather Liners
If you instead provided a valid Ford part number or DTC, a sample report would include: Switch your digital multimeter to the Ohms (
Denotes failures within the body systems, which include lighting, power windows, central locking, and power/heated mirrors.
Because side mirrors are exposed to external weather, moisture can creep past the housing and oxidize the male spade terminals on the rear of the glass.
The represents a "Heated Mirror Circuit Open" failure within the vehicle's body control network. This specific Diagnostic Trouble Code (DTC) is typically managed and triggered by either the Passenger Door Module (PDM) or Driver Door Module (DDM), which monitor the electrical accessories inside the vehicle's door assemblies. When the side mirror heating element fails to complete its electrical circuit, this body code is stored in the system. Decoding the Fault Code: B166A:60
: If the mirror moves slowly, apply a silicone-based lubricant to the pivot point. Do not use WD-40, as it can degrade plastic.
Turn off the vehicle. Pull back the protective rubber accordion boot located between the frame of the car and the front edge of the door. Inspect the bundled wires closely for any split insulation or completely severed copper strands. If you locate a broken wire, splice it back together using a marine-grade heat-shrink butt connector to shield it from future moisture. Clearing the Code