Defective rear defroster timer mechanism

The rear defroster contains a timer mechanism that detects a certain level of heat. When this level is reached, the defroster is shut off. A defect in the timer mechanism will alter the shut off timing. It may shut off immediately, or not at all, depending on the defect.

Table of Contents

• 1. Symptoms
  • 1.1 Rear Defroster Turns Off Immediately
  • 1.2 Rear Defroster Doesn't Turn Off

Symptoms

Rear Defroster Turns Off Immediately

If the rear defroster is turning off immediately, the timer may be reading the wrong heat level and sending a shut off signal right away. This will prevent the defroster from receiving the electrical current it needs to defrost or defog the window.

Rear Defroster Doesn't Turn Off

The rear defroster is designed to turn off after at certain period of time. If it does not turn off, the timer device is not reading the heat level, or it is failing to send the shut off signal.