Circuit Description
The body control module (BCM) monitors the voltage level on the control circuit of the DEFOG relay. The voltage level should be near system voltage while the DEFOG relay is de-energized. The voltage will be pulled low when the BCM energizes the DEFOG relay. The BCM tests the control circuit of the DEFOG relay every 125 milliseconds.
DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC B0283 Electric Rear Defrost Circuit
Conditions for Running the DTC
The ignition is ON.
Conditions for Setting the DTC
One of the following conditions will cause this DTC to set:
| • | The BCM detects a high voltage level on the control circuit of the DEFOG relay, while the relay is energized. |
| • | The BCM detects a low voltage level or an open on the control circuit of the DEFOG relay, while the relay is not energized. |
Conditions for Clearing the DTC
| • | A current DTC clears when the malfunction is no longer present. |
| • | A history DTC clears when the module ignition cycle counter reaches the reset threshold, without a repeat of the malfunction. |
Test Description
The numbers below refer to the step numbers on the diagnostic table.
-
Tests for voltage at the coil side of the DEFOG relay. The HVAC fuse supplies power to the coil side of the DEFOG relay.
-
Verifies that the BCM is providing ground to the DEFOG relay.
-
Tests if ground is constantly being applied to the DEFOG relay.
-
Tests for an open on the control circuit of the DEFOG relay.
Step | Action | Yes | No |
|---|---|---|---|
Schematic Reference: Defogger Schematics Connector End View Reference: Stationary Windows Connector End Views | |||
1 | Did you perform the Diagnostic System Check - Vehicle? | Go to Step 2 | Go to Diagnostic System Check - Vehicle in Vehicle DTC Information |
Does the test lamp illuminate? | Go to Step 3 | Go to Step 9 | |
Does the test lamp turn ON and OFF with each command? | Go to Step 7 | Go to Step 4 | |
Does the test lamp remain illuminated with each command? | Go to Step 6 | Go to Step 5 | |
Test the control circuit of the DEFOG relay for an open or a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 12 | Go to Step 8 | |
6 | Test the control circuit of the DEFOG relay for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 12 | Go to Step 8 |
7 | Inspect for poor connections at the DEFOG relay. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 12 | Go to Step 10 |
8 | Inspect for poor connections at the harness connector of the body control module (BCM). Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 12 | Go to Step 11 |
9 | Repair an open or high resistance in ignition voltage circuit of the DEFOG relay coil. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 12 | -- |
10 | Replace the DEFOG relay. Did you complete the replacement? | Go to Step 12 | -- |
11 | Replace the BCM. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming. Did you complete the replacement? | Go to Step 12 | -- |
12 |
Does the DTC reset? | Go to Step 2 | System OK |
