Pinpoint Test H: The Heated Windshield Will Not Shut Off Automatically
Glass, Frames and Mechanisms
Pinpoint Test H: The Heated Windshield Will Not Shut Off Automatically
Refer to Wiring Diagrams Set 56, Heated Window for schematic and connector information. Electrical Diagrams
Normal Operation
When the engine is running and the heated windshield defrost switch is pressed, the defrost switch supplies a ground input to the Generic Electronic Module (GEM). The GEM (Generic Electronic Module) then activates the left and right heated windshield relays which supply voltage to the heated windshield defrost grids. The left and right heated windshield defrost grids do not share any common power or ground circuits. The heated windshield defrost switch Light Emitting Diode (LED) is illuminated whenever the right heated windshield relay is active.
- DTC B2256 (Front Window Heater Relay Short to Ground)- Sets when an open or short to ground is detected in the left and right heated windshield relay coil control circuit.
This pinpoint test is intended to diagnose the following:
- Left heated windshield relay
- Right heated windshield relay
- Wiring, terminals or connectors
- GEM (Generic Electronic Module)
PINPOINT TEST H : THE HEATED WINDSHIELD WILL NOT SHUT OFF AUTOMATICALLY
NOTICE: Use the correct probe adapter(s) from the Flex Probe Kit when making measurements. Failure to use the correct probe adapter(s) may damage the connector.
H1 CHECK THE HEATED WINDSHIELD DEFROST SWITCH LED (Light Emitting Diode) STATUS
- Start the engine.
- With the engine running, check the heated windshield defrost switch LED (Light Emitting Diode) status.
Is the heated windshield defrost switch LED (Light Emitting Diode) illuminated?
Yes
GO to H2.
No
GO to H6.
H2 CHECK THE HEATED WINDSHIELD DEFROST SWITCH LED (Light Emitting Diode) STATUS WITH THE RIGHT HEATED WINDSHIELD RELAY DISCONNECTED
- Ignition OFF.
- Disconnect: Right Heated Windshield Relay.
- Start the engine.
- With the engine running, check the heated windshield defrost switch LED (Light Emitting Diode) status.
Is the heated windshield defrost switch LED (Light Emitting Diode) illuminated?
Yes
GO to H3.
No
GO to H4.
H3 CHECK THE HEATED WINDSHIELD DEFROST SWITCH LED (Light Emitting Diode) STATUS WITH THE RIGHT HEATED WINDSHIELD GRID FUSE REMOVED
- Ignition OFF.
- Disconnect: BJB (Battery Junction Box) Fuse 2 (40A).
- Start the engine.
- With the engine running, check the heated windshield defrost switch LED (Light Emitting Diode) status.
Is the heated windshield defrost switch LED (Light Emitting Diode) illuminated?
Yes
REPAIR circuit 31S-HB6 (BK/YE) for a short to voltage. TEST the system for normal operation.
No
REPAIR circuit 64S-HB25 (BK/BU) for a short to voltage. TEST the system for normal operation.
H4 CHECK THE HEATED WINDSHIELD RELAY CONTROL CIRCUIT FOR A SHORT TO GROUND
NOTICE: The following step uses a test light to simulate normal circuit loads. Use only the test light recommended in the Special Tools table at the beginning. To avoid connector terminal damage, use the Flex Probe Kit for the test light probe connection to the vehicle. Do not use the test light probe directly on any connector.
- Connect a 12-volt incandescent test light between right heated windshield relay socket pin 1, circuit 15-HB7 (GN/BU) and right heated windshield relay socket pin 2, circuit 31S-HB7 (BU/RD).
Does the test light illuminate?
Yes
GO to H5.
No
INSTALL a new right heated windshield relay. TEST the system for normal operation.
H5 CHECK THE HEATED WINDSHIELD RELAY CONTROL CIRCUIT FOR A SHORT TO GROUND WITH THE GEM (Generic Electronic Module) DISCONNECTED
NOTICE: The following step uses a test light to simulate normal circuit loads. Use only the test light recommended in the Special Tools table at the beginning. To avoid connector terminal damage, use the Flex Probe Kit for the test light probe connection to the vehicle. Do not use the test light probe directly on any connector.
- Ignition OFF.
- Disconnect: GEM (Generic Electronic Module) C201A.
- Connect a 12-volt incandescent test light between right heated windshield relay socket pin 1, circuit 15-HB7 (GN/BU) and right heated windshield relay socket pin 2, circuit 31S-HB7 (BU/RD).
Does the test light illuminate?
Yes
REPAIR circuit 31S-HB7 (BU/RD) for a short to ground. TEST the system for normal operation.
No
GO to H7.
H6 CHECK THE LEFT HEATED WINDSHIELD RELAY
- Ignition OFF.
- Carry out the relay component test on the left heated windshield relay.
Did the left heated windshield relay pass the component test?
Yes
REPAIR circuit 64S-HB12 (BK/BU) for a short to voltage. TEST the system for normal operation.
No
INSTALL a new left heated windshield relay. TEST the system for normal operation.
H7 CHECK FOR CORRECT GEM (Generic Electronic Module) MODULE OPERATION
- Disconnect the GEM (Generic Electronic Module) electrical connectors.
- Check for:
- corrosion.
- pushed-out pins.
- Connect the GEM (Generic Electronic Module) connectors and make sure they seat correctly.
- Operate the system and verify the concern is still present.
Is the concern still present?
Yes
INSTALL a new GEM (Generic Electronic Module). TEST the system for normal operation.
No
The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector.