GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 1999 🢒 Blazer - 4WD - RHD 🢒 Body and Accessories 🢒 Stationary Windows 🢒 Defogger System Check

Step

Action

Normal Result(s)

Abnormal Result(s)*

1
  1. Turn the ignition switch to the ON position.
  2. Depress the defogger switch once.
    • The ON indicator lamp lights.
    • The rear defogger grid becomes warm to the touch within 2 minutes.
    • The defogger turns OFF after 10 minutes.

Go to Rear Window Defogger Inoperative

2

Depress the defogger switch again.
    • The ON indicator lights.
    • The defogger turns OFF after 5 minutes.

Go to Rear Window Defogger Inoperative

3
  1. Depress the defogger switch.
  2. Immediately depress the defogger switch again.
    • The indicator lamp turns OFF.
    • The defogger turns OFF.

Rear Window Defogger Inoperative

4

Electronic HVAC Controller

  1. Inspect the function of the ECC control lead. Refer to HVAC System Check .
  2. Operate the blower mode switch and the temperature controls.

The blower mode switch and the temperature controls function as designed.

Go to HVAC System Check

* Refer to the appropriate symptom diagnostic table for the applicable abnormal result.