DTC B0283
Diagnostic InstructionsDTC Descriptor
DTC B0283

Rear Defogger Circuit

Symptom Byte Information:Symptom Byte List

Diagnostic Fault Information

Circuit

Short to Ground

Open/High Resistance

Short to Voltage

Signal Performance

Control — Relay Coil

B0283 02

B0283 05

B0283 05

—

Ground — Relay Coil

—

B0283 05

—

—

Circuit/System Description

For an overview of the component/system, refer to:Rear Window Defogger Description and Operation

Circuit

Description

B+ — Relay Switch

Supplied from a fuse.

E18 Rear Defogger GridControl — Component

The output circuit is switched to 12 V to activate the component.

Control — Relay Coil

The output circuit is switched to 12 V to activate the component.

E18 Rear Defogger GridGround — Component

Chassis Ground

Ground — Relay Coil

Chassis Ground

Component

Description

KR5 Rear Defogger Relay

A relay is a switch that is actuated by a solenoid.

E18 Rear Defogger Grid

Window defoggers are parallel resistive conductors in or on the glass that heat up when electric power is applied.

K33 HVAC Control Module

The control module controls a series of actuators to ensure optimal heating, ventilation and air conditioning of the passenger compartment. The control module does this by reading values from a variety of sensors and interprets the data and adjusts the actuators accordingly.

A26 HVAC Controls

This device is the user interface to control the HVAC system. Some buttons and indicators are hardwired, some functions use serial data communication.

Conditions for Running the DTC

Ignition » On / Vehicle » In Service Mode

Conditions for Setting the DTC
  • B0283 02Control Circuit=Short to Ground
  • B0283 05Control Circuit=OpenorShort to Battery
Actions Taken When the DTC Sets
  • B0283 02E18 Rear Defogger Grid=Disabled
  • B0283 05E18 Rear Defogger Grid=DisabledorAlways On
Conditions for Clearing the DTC
  • A current DTC will clear when the diagnostic runs and passes.
  • A history DTC will clear after 50 consecutive malfunction-free ignition cycles.
Reference Information

Schematic Reference

Defogger Schematics

Connector End View Reference

Master Electrical Component List

Electrical Information ReferenceScan Tool Reference

Control Module References

Circuit/System Verification
  1. Ignition » On / Vehicle » In Service Mode
  2. Perform the scan tool control function:Rear Defogger»On and Off

    Verify the component turns On and Off:E18 Rear Defogger Grid

    • If the component does not turn On and Off

      Refer to: Circuit/System Testing

    • If the component turns On and Off
  3. All OK.
Circuit/System Testing

    Note: It may take up to 2 min for all vehicle systems to power down before an accurate ground or low reference circuit continuity test can be performed.

  1. Ignition/Vehicle & All vehicle systems » Off
  2. Remove the component:KR5 Rear Defogger Relay
  3. Test for less than 10 Ω between the test points:Ground circuit terminal 85&Ground
    • If 10 Ω or greater
    1. Ground Connection»Disconnect
    2. Test for less than 2 Ω between the test points:Ground circuit terminal 85&Ground Connection
      • If 2 Ω or greater » Repair the open/high resistance in the circuit.
      • If less than 2 Ω » Repair the open/high resistance in the ground connection.
    • If less than 10 Ω
  4. Connect a test lamp between the test points:Control circuit terminal 86&Ground circuit terminal 85
  5. Ignition » On / Vehicle » In Service Mode
  6. Perform the scan tool control function:Rear Defogger»On and Off

    Verify the test lamp turns On and Off.

    • If the test lamp is always Off
    1. Ignition/Vehicle » Off & Remove » Test lamp
    2. Disconnect the electrical connector:K33 HVAC Control Module
    3. Test for infinite resistance between the test points:Control circuit terminal 86@Relay Socket&Ground
      • If less than infinite resistance » Repair the short to ground on the circuit.
      • If infinite resistance
    4. Test for less than 2 Ω between the test points:Control circuit terminal 86@Relay Socket&Terminal 19 X2@Control module harness
      • If 2 Ω or greater » Repair the open/high resistance in the circuit.
      • If less than 2 Ω » Replace the component:K33 HVAC Control Module
    • If the test lamp is always On
    1. Ignition/Vehicle » Off & Remove » Test lamp
    2. Disconnect the electrical connector:K33 HVAC Control Module
    3. Ignition » On / Vehicle » In Service Mode
    4. Test for less than 1 V between the test points:Control circuit terminal 86@Relay Socket&Ground
      • If 1 V or greater » Repair the short to voltage on the circuit.
      • If less than 1 V » Replace the component:K33 HVAC Control Module
    • If the test lamp turns On and Off
  7. Test or replace the component:KR5 Rear Defogger Relay
Component TestingRelay Test
  1. Ignition/Vehicle » Off
  2. Remove the component:KR5 Rear Defogger Relay
  3. Test for 70 to 110 Ω between the test points:Component terminal 85&Component terminal 86
    • If not between 70 and 110 Ω

      Replace the component:KR5 Rear Defogger Relay

    • If between 70 and 110 Ω
  4. Test for infinite resistance between the test points:
    • Component terminal 30&85
    • Component terminal 30&86
    • Component terminal 30&87
    • Component terminal 85&87
    • If less than infinite resistance

      Replace the component:KR5 Rear Defogger Relay

    • If infinite resistance
  5. Connect a 3 A fused jumper wire between the test points:Component terminal 86&12 V

    Connect a jumper wire between the test points:Component terminal 85&Ground

  6. Test for less than 2 Ω between the test points:Component terminal 30&Component terminal 87
    • If 2 Ω or greater

      Replace the component:KR5 Rear Defogger Relay

    • If less than 2 Ω
  7. All OK.
Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair:Diagnostic Repair Verification