DTC B0283
Diagnostic Instructions
DTC Descriptors
| DTC B0283 02: Rear Defogger Circuit Short to
Ground |
| DTC B0283 05: Rear Defogger Circuit High
Voltage/Open |
Diagnostic Fault Information
Circuit
|
Short to Ground
|
Open/High Resistance
|
Short to Voltage
|
Signal Performance
|
Rear Window Defogger Relay Switch B+
|
1
|
1
|
-
|
-
|
HVAC Control
|
U1510 00
|
U1510 00
|
U1510 00
|
-
|
Rear Window Defogger Relay Control
|
B0283 02
|
B0283 05
|
B0283 05
|
-
|
Rear Window Defogger Grid Control
|
1
|
1
|
2
|
-
|
Rear Window Defogger Relay Coil Ground
|
-
|
1
|
1
|
-
|
Rear Window Defogger Grid Ground
|
-
|
1
|
1
|
-
|
1. Rear Defogger Inoperative
2. Rear Defogger Always ON
|
|
| |
Circuit/System Description
When the HVAC control module receives a rear window defog
request from the HVAC control faceplate, the HVAC control module
will supply voltage to the relay coil. Battery positive voltage is
supplied at all times to the relay switched input and the relay
coil is always grounded. This allows current from the relay
switched input to flow through the switch contacts and out the
relay switched output to the rear window defogger grid.
Conditions for Running the DTC
The system voltage must be between 10.8-16 V.
Conditions for Setting the DTC
B0283 02
The HVAC control module detects a short to ground in the relay
control circuit.
B0283 05
The HVAC control module detects a short to voltage or an open/high
resistance in the relay control circuit.
Action Taken When the DTC Sets
| • |
If DTC B0283 02 is current,
the rear window defogger grid will operate continuously.
|
| • |
If DTC B0283 05 is current,
the rear window defogger grid will be inoperative. |
Conditions for Clearing the DTC
| • |
The DTC will be current for as
long as the fault is present. |
| • |
When the fault is no longer
present, the DTC will be a history DTC. |
| • |
A history DTC will clear after
50 ignition cycles. |
Reference Information
Schematic Reference
Defogger Schematics
Connector End View Reference
Component Connector End Views
Description and Operation
Rear Window Defogger Description and Operation
Electrical Information Reference
Scan Tool Reference
Control Module References for scan tool information
Circuit/System Verification
Engine running, command the E18 Rear Defogger Grid ON and OFF by
pressing and depressing the heated rear window switch. The E18 Rear
Defogger Grid should turn ON and OFF when changing between the
commanded states.
Circuit/System Testing
| 1. |
Ignition OFF, disconnect the
KR5 Rear Defogger Relay. |
| 2. |
Test for less than 5 Ω
between the ground circuit terminal 2 and ground |
| ⇒ |
If greater than the specified range, test the
ground circuit for an open/high resistance |
| 3. |
Connect a test lamp between
the control circuit terminal 1 and the ground circuit terminal
2. |
| 4. |
Engine running, command the
E18 Rear Defogger Grid ON and OFF by pressing and depressing the
heated rear window switch. The test lamp should turn ON and OFF
when changing between the commanded states. |
| ⇒ |
If the test lamp is always ON, test the control
circuit for a short to voltage. If the circuit tests normal,
replace the K33 HVAC 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, replace the K33 HVAC Control Module. |
| 5. |
If all circuits test normal,
test or replace the KR5 Rear Defogger Relay. |
Component Testing
Relay Test
| 1. |
Ignition OFF, disconnect the
KR5 Rear Defogger Relay. |
| 2. |
Test for 60-180 Ω
between terminals 1 and 2. |
| ⇒ |
If the resistance is not within the specified
range, replace the KR5 Rear Defogger Relay. |
| 3. |
Test for infinite resistance
between the following terminals: |
| ⇒ |
If not the specified value, replace the KR5 Rear
Defogger Relay. |
| 4. |
Install a 5 A fused jumper
wire between relay terminal 2 and 12 V. Install a jumper wire
between relay terminal 1 and ground. Test for less than 2 Ω
between terminals 3 and 5. |
| ⇒ |
If greater than the specified range, replace the
KR5 Rear Defogger Relay. |
Repair Instructions
Perform the
Diagnostic Repair Verification after completing the diagnostic
procedure.
|
