GM Service Manual Online
For 1990-2009 cars only

Diagnostic Aids

The Wash mode for this diagnostic procedure is denied as the mode when the wiper switch is OFF and only the windshield washer switch has been activated. When the washer switch is activated with the wiper switch OFF, the wipers should wipe the windshield 3-5 times and then park.

Test Description

The numbers below refer to the step numbers on the diagnostic table.

  1. This step will pinpoint which special wiper functions are inoperative. The wipers should operate for all active windshield wiper switch positions. When the wiper switch is OFF and only the windshield washer switch is activated, the wipers should wipe the windshield 3-5 times and then park.

  1. This step will help to pinpoint which special circuit or component may be involved in the malfunction. When the Wash, and Park modes are inoperative as well as the Intermittent mode, the windshield wiper switch mist/off/low signal circuit and associated components are suspect. When the wipers operate for the Park mode but the Intermittent and Wash modes are both inoperative, suspect the accessory voltage feed circuit of the FRT WIPER Relay or an associated component.

Step

Action

Yes

No

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. Operate the windshield wiper switch through all switch positions.
  3. Turn the windshield wiper switch OFF.
  4. With the windshield wiper switch OFF, operate the front windshield washer switch to ON.

Do the windshield wipers operate well?

Go to Testing for Intermittent Conditions and Poor Connections

Go to Step 3

3

Are the windshield wipers completely inoperative?

Go to Step 10

Go to Step 4

4

Are the windshield wipers inoperative for every mode except High speed?

Go to Step 11

Go to Step 5

5

Are the wipers inoperative in the Intermittent mode?

Go to Step 6

Go to Step 7

6

In addition to the Intermittent mode, are the windshield wipers inoperative for one or both of the following two modes?

    • Wash
    • Park

Go to Step 17

Go to Step 14

7

Important: When the windshield washer mode is activated with the windshield wiper switch OFF, the windshield wipers should wipe the windshield 3-5 times and then park.

Are the wipers inoperative for only the Wash mode?

Go to Step 12

Go to Step 8

8

Are the wipers inoperative for only the Park mode?

Go to Step 13

Go to Step 9

9

The wipers are inoperative for only the High speed mode.

  1. Disconnect the windshield wiper motor harness connector.
  2. With a test lamp connected to ground, probe the windshield wiper motor high speed circuit of the harness connector.
  3. Operate the windshield wiper switch to the high speed position.

Does the test lamp illuminate?

Go to Step 24

Go to Step 22

10

The windshield wipers are totally inoperative.

  1. Disconnect the windshield wiper motor harness connector.
  2. With a test lamp connected to battery positive voltage, probe the windshield wiper motor ground circuit.

Does the test lamp illuminate?

Go to Step 16

Go to Step 29

11

The windshield wipers operate only in High speed.

  1. Disconnect the windshield wiper motor harness connector.
  2. With a test lamp connected to ground, probe the windshield wiper motor low speed circuit of the harness connector.
  3. Operate the windshield wiper switch to the low speed position.

Does the test lamp illuminate?

Go to Step 24

Go to Step 20

12

The windshield wipers are inoperative for only the Wash mode.

  1. Disconnect the body control module (BCM) J5 5 harness connector.
  2. With a test lamp connected to ground, probe the windshield washer pump control circuit of the harness connector.
  3. Operate the windshield washer switch to ON.

Does the test lamp illuminate?

Go to Step 25

Go to Step 21

13

The wipers are inoperative for only the Park mode.

  1. Disconnect the windshield wiper motor harness connector.
  2. Test for continuity between the windshield wiper motor park switch signal circuit and ground circuit of the wiper motor, at the wiper motor pins.

Is there continuity?

Go to Step 15

Go to Step 24

14

The wipers are inoperative for only the Intermittent mode.

  1. Disconnect the body control module (BCM) J5 5 harness connector.
  2. With a test lamp connected to ground, probe the windshield wiper switch pulse delay signal circuit of the harness connector.
  3. Operate the windshield washer switch through all of the Intermittent positions.

Is the test lamp illuminated for all of the Intermittent positions?

Go to Step 25

Go to Step 23

15

  1. Connect the windshield wiper motor harness connector.
  2. Disconnect the FRT WIPER Relay.
  3. With a test lamp connected to battery positive voltage, probe the windshield wiper motor park switch signal circuit of the underhood fuse block.

Does the test lamp illuminate?

Go to Step 33

Go to Step 30

16

  1. Connect the test lamp between ground and the windshield wiper motor high speed circuit of the harness connector.
  2. Operate the windshield wiper switch to the high speed position.
  3. Connect the test lamp between ground and the windshield wiper motor low speed circuit of the harness connector.
  4. Operate the windshield wiper switch to the low speed position.

Does the test lamp illuminate for both the high and the low positions?

Go to Step 24

Go to Step 26

17

  1. Turn OFF the ignition.
  2. Disconnect the FRT WIPER Relay.
  3. Turn ON the ignition, with the engine OFF.
  4. With a test lamp connected to ground, probe the accessory voltage feed circuits of the FRT WIPER Relay, at the underhood fuse block.

Does the test lamp illuminate?

Go to Step 18

Go to Step 28

18

  1. Turn OFF the ignition.
  2. Connect a 3-amp fused jumper between the accessory voltage feed circuit and the windshield wiper switch mist/off/low signal circuit, at the underhood fuse block.
  3. Turn ON the ignition, with the engine OFF.
  4. Turn the windshield wiper switch to the Intermittent position.
  5. With a test lamp connected to ground, probe the windshield wiper switch mist/off/low signal circuit, at the windshield wiper switch terminal.

Does the test lamp illuminate?

Go to Step 19

Go to Step 27

19

With the test lamp connected to ground, probe the windshield wiper switch low speed circuit, at the windshield wiper switch terminal.

Does the test lamp illuminate?

Go to Step 33

Go to Step 26

20

Test the windshield wiper motor low speed circuit for an open.

Did you find and correct the condition?

Go to Step 35

Go to Step 26

21

Test the windshield washer pump control circuit for an open.

Did you find and correct the condition?

Go to Step 35

Go to Step 26

22

Test the windshield wiper motor high speed circuit for an open.

Did you find and correct the condition?

Go to Step 35

Go to Step 26

23

Test the windshield wiper switch pulse delay signal circuit for an open.

Did you find and correct the condition?

Go to Step 35

Go to Step 26

24

Inspect for poor connections at the harness connector of the windshield wiper motor.

Did you find and correct the condition?

Go to Step 35

Go to Step 32

25

Inspect for poor connections at the harness connector of the BCM.

Did you find and correct the condition?

Go to Step 35

Go to Step 34

26

Inspect for poor connections at the harness connector of the windshield wiper washer switch.

Did you find and correct the condition?

Go to Step 35

Go to Step 31

27

Repair the windshield wiper switch circuit for an open or a high resistance.

Did you complete the repair?

Go to Step 35

--

28

Repair the accessory voltage feed circuit for an open or a high resistance.

Did you complete the repair?

Go to Step 35

--

29

Repair the open ground circuit.

Did you complete the repair?

Go to Step 35

--

30

Repair the windshield wiper motor park switch signal circuit for an open or a high resistance.

Did you complete the repair?

Go to Step 35

--

31

Replace the windshield wiper washer switch.

Did you complete the replacement?

Go to Step 35

--

32

Replace the windshield wiper motor.

Did you complete the replacement?

Go to Step 35

--

33

Replace the FRT WIPER relay.

Did you complete the replacement?

Go to Step 35

--

34

Replace the BCM. Refer to Body Control Module Replacement .

Did you complete the replacement?

Go to Step 35

--

35

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 2