2010 Cadillac Truck SRX AWD V6-3.0L Page 153
瀚慖f DTC is present, refer to Electrical Auxiliary Heater Signal Circuit Malfunction.
Circuit/System Testing
Electrical Auxiliary Heater Control Circuit Malfunction
1. Ignition OFF, disconnect the X2 harness connector at the K33 HVAC Control Module and the X1 harness connector at the E40 Electrical
Auxiliary Heater.
2. Ignition ON, verify that a test lamp illuminates between the ignition circuit terminal 2 X1 and ground.
瀚慖f the test lamp does not illuminate, test the ignition circuit for a short to ground or an open/high resistance.
3. Test for less than 0.3 V between the control circuit terminal 7 X2 at the K33 HVAC Control Module harness connector and ground.
瀚慖f greater than the specified range, test the control circuit for a short to voltage.
4. Ignition OFF, test for infinite resistance between the control circuit terminal 7 X2 at the K33 HVAC Control Module harness connector and
ground.
瀚慖f less than the specified value, test the control circuit for a short to ground.
5. Test for less than 5 ohm between the K33 HVAC Control Module control circuit terminal 7 X2 and control circuit terminal 1 X1 at the E40
Electrical Auxiliary Heater harness connector.
瀚慖f greater than the specified value, test the control circuit for an open/high resistance.
6. If all circuits test normal, replace the E40 Electrical Auxiliary Heater and verify the DTC does not reset.
Electrical Auxiliary Heater Signal Circuit Malfunction
1. Ignition OFF, disconnect the X2 harness connector at the K33 HVAC Control Module and the harness connectors at the E40 Electrical
Auxiliary Heater.
2. Ignition ON, verify that a test lamp illuminates between the B+ circuit terminal 1 X2 at the E40 Electrical Auxiliary Heater harness connector
and ground.
瀚慖f the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.
3. Verify that a test lamp illuminates between the B+ circuit terminal 1 X2 and ground circuit terminal 1 X3.
瀚慖f the test lamp does not illuminate, test the ground circuit for an open/high resistance.
4. Verify that a test lamp illuminates between the ignition circuit terminal 2 X1 and ground circuit terminal 1 X3.
瀚慖f the test lamp does not illuminate, test the ignition circuit for a short to ground or an open/high resistance.
5. Test for less than 0.3 V between the signal circuit terminal 5 X2 at the K33 HVAC Control Module harness connector and ground.
瀚慖f greater than the specified range, test the signal circuit for a short to voltage.
6. Ignition OFF, test for infinite resistance between the signal circuit terminal 5 X2 at the K33 HVAC Control Module harness connector and
ground.
瀚慖f less than the specified value, test the signal circuit for a short to ground.
7. Test for less than 5 ohm between the K33 HVAC Control Module signal circuit terminal 5 X2 and signal circuit terminal 4 X1 at the E40
Electrical Auxiliary Heater harness connector.
瀚慖f greater than the specified value, test the circuit for an open/high resistance.
8. If all circuits test normal, replace the E40 Electrical Auxiliary Heater and verify the DTC does not reset.
Repair Instructions
Perform the Diagnostic Repair Verification (See: Verification Tests) after completing the diagnostic procedure.
Control Module References (See: Testing and Inspection/Programming and Relearning) for HVAC control module replacement, setup, and
