Technician A says that the rear defogger and heated mirror system operate on the same circuit. Technician B says that a heated mirror heating element can be repaired similar to a rear defogger grid. Who is right?

• A. A only
• B. B only
• C. Both A and B
• D. Neither A nor B

Answer: (A)

The idea being tested is how heated components in a vehicle are wired and serviced. In many designs, the rear defogger and the mirror heater share the same control circuit: the defogger switch and its power supply are arranged so that activating the defogger also powers the heated mirrors. This keeps wiring simpler and ensures both heat when needed, with proper protection like fuses and relays in the same circuit path.

Repairing a heated mirror element the same way as a rear defogger grid isn’t appropriate. The mirror heater is a sealed, integrated element within the mirror assembly, and when it fails you typically replace the mirror or the entire assembly rather than attempting a repair like you might with a defogger grid.