GM Service Manual Online
For 1990-2009 cars only

Step

Action

Yes

No

Schematic Reference: Outside Rearview Mirror Schematics

Connector End View Reference: Master Electrical Component List

1

Did you perform the Diagnostic System Check - Vehicle?

Go to Step 2

Go to Diagnostic System Check - Vehicle

2

  1. Turn ON the ignition, with the engine OFF.
  2. Depress the heated mirror switch.

Do the heated mirrors operate normally?

Go to Testing for Intermittent Conditions and Poor Connections

Go to Step 3

3

Are both heated mirrors inoperative?

Go to Step 4

Go to Step 10

4

  1. Turn ON the ignition, with the engine OFF.
  2. With a test lamp connected to ground, probe the ignition 3 voltage circuit at the heated mirror switch harness connector.

Did the test lamp illuminate?

Go to Step 5

Go to Step 15

5

  1. Turn ON the ignition, with the engine OFF.
  2. With a test lamp connected to a good ground, probe the heating element supply voltage circuit at the heated mirror switch harness connector.
  3. Depress the heated mirror switch.

Does the test lamp illuminate when the switch is depressed?

Go to Step 6

Go to Step 12

6

  1. Remove the heated mirror relay.
  2. Turn ON the ignition, with the engine OFF.
  3. With a test lamp connected to ground, probe the heating element supply voltage circuit for the control side of the relay at the I/P fuse block.
  4. Depress the heated mirror switch.

Does the test lamp illuminate when the switch is depressed?

Go to Step 7

Go to Step 16

7

With a test lamp connected to battery voltage, probe the relay ground circuit at the I/P fuse block.

Does the test lamp illuminate?

Go to Step 8

Go to Step 17

8

  1. Turn ON the ignition, with the engine OFF.
  2. With a test lamp connected to ground, probe the ignition 3 voltage circuit for the heated mirror relay at the I/P fuse block.

Does the test lamp illuminate?

Go to Step 9

Go to Step 15

9

  1. Turn ON the ignition, with the engine OFF.
  2. Connect a 15-amp fused jumper between the ignition 3 voltage circuit and the heating element supply voltage circuit at the I/P fuse block.

Do the heated mirrors operate?

Go to Step 13

Go to Step 16

10

  1. Disconnect the inoperative heated mirror glass.
  2. Connect a test lamp between the mirror heating element supply voltage circuit at the inoperative mirror harness connector and a good ground.
  3. Depress the heated mirror switch to activate the system.

Does the test lamp illuminate?

Go to Step 11

Go to Step 15

11

With the system still active, connect a test lamp between the mirror heating element supply voltage circuit and the mirror ground circuit.

Does the test lamp illuminate?

Go to Step 14

Go to Step 17

12

Inspect for poor connections at the heated mirror switch. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs.

Did you find and correct the condition?

Go to Step 21

Go to Step 18

13

Inspect for poor connections at the heated mirror relay. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs.

Did you find and correct the condition?

Go to Step 21

Go to Step 19

14

Inspect for poor connections at the heated mirror glass. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs.

Did you find and correct the condition?

Go to Step 21

Go to Step 20

15

Repair the open or short to ground in the ignition 3 voltage circuit. Refer to Circuit Testing and Wiring Repairs.

Did you find and correct the condition?

Go to Step 21

--

16

Repair the open or short to ground in the mirror heating element supply voltage circuit. Refer to Circuit Testing and Wiring Repairs.

Did you find and correct the condition?

Go to Step 21

--

17

Repair the open in the ground circuit. Refer to Circuit Testing and Wiring Repairs.

Did you complete the repair?

Go to Step 21

--

18

Replace the heated mirror switch. Refer to Accessory Switch Replacement.

Did you complete the repair?

Go to Step 21

--

19

Replace the heated mirror relay. Refer to Relay Replacement.

Did you complete the repair?

Go to Step 21

--

20

Replace the heated mirror glass. Refer to Outside Rearview Mirror Glass Replacement - Upper.

Did you complete the repair?

Go to Step 21

--

21

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 3