Rear Wiper System Malfunction
Diagnostic Instructions
Diagnostic Fault Information
Circuit
|
Short to Ground
|
Open/High Resistance
|
Short to Voltage
|
Signal Performance
|
Rear Wiper Switch Signal
|
2
|
1
|
1
|
--
|
Rear Window Wiper Control
|
1
|
1
|
2
|
--
|
Rear Window Wiper Relay Control
|
B370B 02
|
1
|
2
|
--
|
Rear Window Wiper Ground
|
--
|
1
|
1
|
--
|
1. Washer Inoperative.
2. Washer Always ON.
|
Circuit/System Description
The body control module (BCM) controls the single speed rear
wiper motor by its active high output to the external rear wiper
motor relay. When the BCM activates its output and applies battery
to the coil of the relay, the relay energizes, allowing battery
voltage from the fuse to be applied through the switched contacts
of the rear wiper motor relay to the control input of the rear
wiper motor. The motor then operates continuously at low speed.
Reference Information
Schematic Reference
Wiper/Washer Schematics
Connector End View Reference
Component Connector End Views
Description and Operation
Wiper/Washer System Description and Operation
Electrical Information Reference
Scan Tool Reference
Control Module References for scan tool information
Circuit/System Verification
Operate the rear wiper by using the S82 Windscreen
Wiper/Washer Switch in the continuous and the intermittent
position. Verify the M45 Rear Wiper Motor activates. Verify
the tailgate is closed.
Circuit/System Testing
Multifunction Switch Circuit Malfunction
- Ignition OFF, disconnect the harness connector at the
S82 Windscreen Wiper/Washer Switch.
- Test for less than 5 Ω between the ground circuit
terminal 2 and ground.
⇒ |
If greater than the specified value, test the
ground circuit for an open/high resistance and a short to voltage.
If the circuit tests normal, replace the K9 Body Control
Module. |
- Disconnect the X2 harness connector at the
K9 Body Control Module.
- Test for less than 5 Ω between the signal circuit
terminal 4 at the S82 Windscreen Wiper/Washer Switch
harness connector and the X2 harness connector terminal 12 at
the K9 Body Control Module.
⇒ |
If greater than the specified value, test the
signal circuit for an open/high resistance and a short to
voltage. |
- If all circuits test normal, replace the
S82 Windscreen Wiper/Washer Switch.
Rear Wiper Motor Circuit Malfunction
- Ignition OFF, disconnect the harness connector at the
M45 Rear Wiper Motor.
- Test for less than 5 Ω between the ground circuit
terminal B and ground.
⇒ |
If greater than the specified range, test the
ground circuit for an open/high resistance or a short to
voltage. |
- Test for less than 5 Ω between the control
circuit terminal A and ground.
⇒ |
If greater than the specified range, test the
ground circuit for an open/high resistance or a short to
voltage. |
- Verify a test lamp illuminates between the B+ circuit
terminal C and ground.
⇒ |
If the test lamp does not illuminate, test the B+
circuit terminal C for an open/high resistance and a short to
ground. |
⇒ |
If all circuits test normal, test or replace the
X50A Fuse Block - Underhood. |
- Install a test lamp between the control circuit
terminal A and the ground circuit terminal B.
- Using the S82 Windscreen Wiper/Washer Switch,
command the rear wiper ON and OFF. The test lamp should turn ON and
OFF as commanded. Observe this in the switch position continuous
and intermittent.
⇒ |
If the test lamp is always ON, test the control
circuit for a short to voltage. If the circuit tests normal,
replace the K9 Body Control Module. |
⇒ |
If the test lamp is always OFF, test the control
circuit for a short to ground or an open/high resistance. If the
circuit tests normal, test or replace the K9 Body Control
Module. |
- If all circuits test normal, test or replace the
M45 Rear Wiper Motor.
Component Testing
Output Control Test
Ignition ON, command the Rear Wiper Command On and OFF with a
scan tool. Observe the KR7 Rear Wiper Relay clicks and the
M45 Rear Wiper Motor runs.
⇒ |
If the KR7 Rear Wiper Relay does not work,
replace the X50A Fuse Block - Underbonnet. |
⇒ |
If the KR7 Rear Wiper Relay does work, but
the M45 Rear Wiper Motor does not run, test the M45 Rear
Wiper Motor ground and control circuit. |
⇒ |
If all circuits test normal, replace the
M45 Rear Wiper Motor. |
Relay Test
- Ignition OFF, disconnect the harness connector X4
at the K9 Body Control Module.
- Test for 110-160 Ω between terminal 8 X4 and
ground.
⇒ |
If the resistance is not within the specified
range, test the control circuit for a short to ground, short to
voltage or an open/high resistance. |
⇒ |
If all circuits test normal, test or replace the
X50A Fuse Block - Underhood. |
Dynamic Test
- Ignition OFF, disconnect the harness connector at the
M45 Rear Wiper Motor.
- Install a 25 A fused jumper wire between the
control terminal A and 12 V. Install a jumper wire between the
ground terminal B and ground.
- Verify the M45 Rear Wiper Motor is
operating.
⇒ |
If the M45 Rear Wiper Motor is not operating,
replace the M45 Rear Wiper Motor. |
Static Test
- Ignition OFF, remove the S82 Windscreen
Wiper/Washer Switch.
- Test for 610-660 Ω between the signal
terminals 2 and 4 at the S82 Windscreen Wiper/Washer
Switch in the continuous position.
⇒ |
If the resistance is not within the specified
range, replace the S82 Windscreen Wiper/Washer Switch. |
- Test for 1 800-2 200 Ω between the
signal terminals 2 and 4 at the S82 Windscreen
Wiper/Washer Switch in the intermittent position.
⇒ |
If the resistance is not within the specified
range, replace the S82 Windscreen Wiper/Washer Switch. |
Repair Instructions
Perform the
Diagnostic Repair Verification after completing the diagnostic
procedure.
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