GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Isuzu 🢒 2006 🢒 Ascender - 4WD 🢒 Vehicle Control Systems 🢒 Vehicle DTC Information 🢒 Rear Wiper Inoperative

Test Description

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

  1. If any of the listed switches fails, indicating an open liftglass or liftgate the rear wiper/washer will not operate.

    2.

  2. This step determines if the liftgate module (LGM) is receiving the correct switch position message from the body control module (BCM).

    3.

  3. This step determines if the LGM is attempting to operate rear wiper motor in the requested operating mode.

    4.

  4. This step tests the resistance through the rear wiper switch. The measured resistance will be highest in the OFF position and reduce as the switch is turned from positions 1 through 3.

Step

Action

Value(s)

Yes

No

Schematic Reference: Wiper/Washer Schematics

Connector End View Reference: Wiper/Washer Connector End Views

DEFINITION: One or more of the rear wiper operating modes are inoperative.

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.
  2. Operate the rear wiper switch through all the switch positions.

Does the rear window wiper operate normally?

--

Go to Testing for Intermittent Conditions and Poor Connections

Go to Step 3

3

  1. Install a scan tool.
  2. Display the liftgate module (LGM) data list.
  3. Observe the following parameters while operating the respective switches. Refer to Scan Tool Data List for typical values.
    4. • Liftgate ajar switch
    • Liftglass ajar switch

Did the scan tool indicate the correct switch positions?

--

Go to Step 4

Go to Symptoms - Lighting Systems

4

  1. Observe the requested Rear Wiper parameter in LGM data list.
  2. Operate the rear wiper switch through all the switch positions.

Does the scan tool indicate the correct requested Rear Wiper parameter in relation to the switch position?

--

Go to Step 5

Go to Step 6

5

  1. Close the liftglass and liftgate.
  2. Observe the Rear Wiper Mode/Rear Wiper parameter.
  3. Operate the rear wiper switch through all the switch positions.

Does the scan tool indicate the correct Rear Wiper Mode parameter in relation to the switch position?

--

Go to Step 7

Go to Step 18

6

  1. Turn OFF the ignition.
  2. Disconnect the rear wiper switch.
  3. Measure the resistance through the rear wiper switch from the switch power circuit terminal to the signal circuit terminal.
  4. Operate the rear wiper switch through the following switch positions:
    5. • OFF
    • 1
    • 2
    • 3

Does the resistance remain within the specified values from OFF to 3 as the switch is operated through the listed switch positions?

3,100-1,500 ohms

Go to Step 15

Go to Step 11

7
  1. Turn OFF the ignition.
  2. Disconnect the rear wiper motor connector.
  3. Test the rear wiper motor battery voltage supply circuit for an open or short to ground. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

--

Go to Step 20

Go to Step 8

8

Test the rear wiper motor ground circuit for an open or high resistance. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

--

Go to Step 20

Go to Step 9

9
  1. Connect a test lamp between battery voltage circuit and the control circuit of the rear wiper motor connector.
  2. Close the liftglass and liftgate.
  3. Turn ON the ignition with the engine OFF.
  4. Turn the rear wiper switch from OFF to 3.

Did the brightness of the test lamp decrease gradually as the rear wiper switch was turned from OFF to 3?

--

Go to Step 13

Go to Step 10

10
  1. Disconnect the LGM.
  2. Test the rear wiper motor control circuit for an open, a short to ground or a short to voltage. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

--

Go to Step 20

Go to Step 18

11

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

Did you find and correct the condition?

--

Go to Step 20

Go to Step 12

12

Replace the rear wiper switch. Refer to Rear Window Wiper and Washer Switch Replacement .

Is the repair complete?

--

Go to Step 20

--

13

Inspect for poor connections at the rear wiper motor. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .

Did you find and correct the condition?

--

Go to Step 20

Go to Step 14

14

Replace the rear wiper motor. Refer to Rear Window Wiper Motor Replacement .

Is the repair complete?

--

Go to Step 20

--

15

Test the rear window wiper switch signal circuit for an open or short to ground. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

--

Go to Step 20

Go to Step 16

16

Inspect for poor connections at the body control module (BCM). Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .

Did you find and correct the condition?

--

Go to Step 20

Go to Step 17

17

Replace the BCM. Refer to Control Module References for replacement, setup, and programming.

Is the repair complete?

--

Go to Step 20

--

18

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

Did you find and correct the condition?

--

Go to Step 20

Go to Step 19

19

Replace the LGM. Refer to Control Module References for replacement, setup, and programming.

Is the repair complete?

--

Go to Step 20

--

20

Operate the system in order to verify the repair.

Did you correct the condition?

--

System OK

Go to Step 4