B0283
DTC B0283
DTC Descriptors
DTC B0283 02
- Electric Rear Defrost Circuit Short To Ground
DTC B0283 05
- Electric Rear Defrost Circuit Short To Battery Or Open
Diagnostic Fault Information
Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. Initial Inspection and Diagnostic Overview
Circuit/System Description
The body control module (BCM) monitors the voltage level on the supply voltage circuit of the RR DEFOG relay. The voltage level should be low while the RR DEFOG relay is de-energized. The voltage will be near system voltage when the BCM energizes the RR DEFOG relay.
Conditions for Running the DTC
Battery voltage must be between 9-16 volts.
Conditions for Setting the DTC
B0283 02
This DTC will set when the BCM detects a short to ground in the RR DEFOG relay control circuit voltage supply circuit for 1 second or greater.
B0283 05
This DTC will set when the BCM detects a short to voltage or an open/high resistance in the RR DEFOG relay control circuit voltage supply circuit for 1 second or greater.
Action Taken When the DTC Sets
* The BCM stores the DTC to memory.
* The rear window defogger will not operate.
Conditions for Clearing the DTC
* This DTC will change from current to history when the fault is no longer present.
* A history DTC will clear after 100 consecutive ignition cycles if the condition for the malfunction is no longer present.
* The technician issues a scan tool CLEAR DTCs command.
Circuit/System Verification
Ignition ON, command the rear window defogger ON and OFF with a scan tool. Observe the rear window defogger operation as the rear window defogger turns ON and OFF.
If the rear window defogger indicator light does not illuminate, replace the HVAC control module.
Circuit/System Testing
Rear Defogger Malfunction
1. Ignition OFF, disconnect the RR DEFOG relay.
2. Ignition OFF, test for less than 1 ohm of resistance between the coil side ground circuit terminal and ground.
• If greater than the specified range, test for an open/high resistance.
3. Ignition ON, verify that a test lamp does not illuminate between the switch side control circuit terminal and ground.
• If the test lamp illuminates, test the control circuit for a short to voltage.
4. Verify that a test lamp illuminates between the switch side B+ circuit terminal and ground.
• If the test lamp does not illuminate, test the switch side B+ circuit for a short to ground or an open/high resistance. If the circuit tests normal and the switch side circuit fuse is open, test the switch side control circuit terminal for a short to ground.
5. Connect a test lamp between the coil side control circuit terminal and the coil side ground circuit terminal.
6. Command the RR DEFOG relay ON and OFF with a scan tool. 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 BCM.
• 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 BCM.
7. If all circuits test normal, test or replace the RR DEFOG relay.
Component Testing
Relay Test
1. Ignition OFF, disconnect the RR DEFOG relay.
2. Test for 60-180 ohms of resistance between terminals 85 and 86.
• If the resistance is not within the specified range, replace the relay.
3. Test for infinite resistance between the following terminals:
* 30 and 86
* 30 and 87
* 30 and 85
* 85 and 87
• If greater than the specified range, replace the relay.
4. Install a 40-amp fused jumper wire between relay terminal 85 and 12 volts. Install a jumper wire between relay terminal 86 and ground. Test for less than 2 ohms of resistance between terminals 30 and 87.
• If greater than the specified range, replace the relay.
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure. Verification Tests
* Relay Replacement (Attached to Wire Harness) Relay Replacement (Within an Electrical Center)
* Programming and Relearning for HVAC Control Module and BCM setup and programming Programming and Relearning