LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Jeep >> 2024 >> Gladiator Nighthawk, Part Time T/Case Control, Automatic Trans >> Repair and Diagnosis (Single Page) >> Accessories & Equipment >> Communication Devices >> Body Control Module (BCM) - DTCS B10B3-12 To B162A-11 >> DTC Troubleshooting >> B10CA-14 Front Defrost Control Circuit - Circuit Short To Ground Or Open >> Diagnostic Test
April 5, 2026: LEMON Manuals is launched! Read the announcement.

Diagnostic Test

  1. READ AND RECORD DTCS AND ENVIRONMENTAL DATA - ERASE DTCS AND CHECK FOR THE DTC TO RETURN 
    1. With the scan tool, read DTCs in all Electronic Control Units (ECU's) and record on the repair order.
    2. With the scan tool, run a vehicle Scan Report, or record the Environmental Data related to the DTCs.
    3. With the scan tool, erase all DTCs.
    4. Turn the ignition off for a minimum of 10.0 seconds.
    5. Turn the ignition on.
    6. Using the recorded Environmental Data and the When Monitored Conditions above, operate the vehicle in the conditions that set the DTC.
    7. With the scan tool, read Body Control Module (BCM) DTCs.

      Did the DTC return?

      Yes 

      • Go To  2

      No 

  2. CHECK FUSE F44 (10A) FOR AN OPEN 
    NOTE:

    When removing fuses from the PDC Assembly, do not rock or wiggle the fuse sideways during removal. Lift the fuse upward, using fingers or suitable pliers, at the middle of the fuse body and inspect the fuse terminals for proper contact.

    1. Turn the ignition off.
    2. Remove the indicated fuse from the Power Distribution Center (PDC) Assembly.
    3. Check the fuse for an open.

      Is the fuse open?

      Yes 

      • Replace the fuse and check the system operation. If the fuse continues to open, repair the circuit for a short to ground. Use the wiring diagram as a guide to trace the circuit and look for any in-line connectors to help isolate the location of the short.
      • Perform the BODY VERIFICATION TEST. Refer to: BODY VERIFICATION TEST .

      No 

      • Install the fuse and Go To  3
  3. SUBSTITUTE THE WINDSHIELD HEATER RELAY - ERASE DTCS AND CHECK FOR THE DTC TO RETURN 
    NOTE:

    When removing a relay from the PDC Assembly, do not rock or wiggle the relay sideways during removal. Lift the relay upward, using fingers or suitable pliers, at the middle of the relay body and inspect the relay terminals for proper contact.

    NOTE:

    Additional DTCs may set in other Electronic Control Units (ECU's) when substituting relays in the PDC Assembly.

    1. Turn the ignition off.
    2. Remove the relay, for the circuit being tested, from the Power Distribution Center (PDC) Assembly.
    3. Substitute the relay with a similar known good relay in the PDC Assembly.
    4. Turn the ignition on.
    5. With the scan tool, erase DTCs.
    6. Using the Environmental Data or When Monitored Conditions above, operate the vehicle under the conditions that set the DTC.
    7. With the scan tool, read BCM DTCs.

      Did the DTC return?

      Yes 

      • Go To  4

      No 

      • Replace the relay that caused the fault. With the scan tool, erase any additional DTCs that may have set when the relays were substituted.
      • Perform the BODY VERIFICATION TEST. Refer to: BODY VERIFICATION TEST .
  4. DISCONNECT THE BCM HARNESS CONNECTOR(S) AND CHECK THE (C902) WINDSHIELD HEATER RELAY CONTROL CIRCUIT FOR CONTINUITY TO GROUND AT THE WINDSHIELD HEATER RELAY TERMINAL 
    1. The ignition must be off when checking a circuit for continuity to ground.
    2. Remove the relay, for the circuit being tested, from the Power Distribution Center (PDC) Assembly.
    3. Disconnect all Electronic Control Unit (ECU) harness connectors containing the circuit being tested. Note:  Use the wiring diagram as a guide to follow the path of the circuit.
    4. Connect the negative lead of the DVOM to a known good ground.
    5. Connect the positive lead of the DVOM to the circuit being tested, at the relay terminal in the Power Distribution Center (PDC) Assembly, and check for continuity between the circuit and ground.
      NOTE:

      When probing a circuit at any harness connector, always use an appropriate probing tool to prevent any possible damage to the harness connector terminals.

      NOTE:

      There should be no continuity between ground and the circuit being tested.

      Is there continuity between ground and the circuit being tested?

      Yes 

      • Go To  5

      No 

      • Go To  6
  5. DISCONNECT THE POWER DISTRIBUTION CENTER (PDC) ASSEMBLY HARNESS CONNECTOR(S) AND CHECK THE (C902) WINDSHIELD HEATER RELAY CONTROL CIRCUIT FOR A SHORT TO GROUND 
    1. The ignition must be off when checking a circuit for continuity to ground.
    2. Isolate the circuit by disconnecting the Power Distribution Center (PDC) Assembly harness connector containing the circuit being tested. Note:  Use the wiring diagram as a guide to follow the path of the circuit.
    3. Connect the negative lead of the DVOM to a known good ground.
    4. Connect the positive lead of the DVOM to the circuit being tested at the PDC Assembly harness connector and check for continuity between the circuit and ground.
      NOTE:

      When probing a circuit at any harness connector, always use an appropriate probing tool to prevent any possible damage to the harness connector terminals.

      NOTE:

      There should be no continuity between ground and the circuit being tested.

      Is there continuity between ground and the circuit being tested?

      Yes 

      • Repair the circuit for a short to ground. Use the wiring diagram as a guide to trace the circuit and look for any in-line connectors to help isolate the location of the short.
      • Perform the BODY VERIFICATION TEST. Refer to: BODY VERIFICATION TEST .

      No 

      • Go To  8
  6. CHECK THE (C902) WINDSHIELD HEATER RELAY CONTROL CIRCUIT FOR AN OPEN OR HIGH RESISTANCE BETWEEN THE BCM AND THE WINDSHIELD HEATER RELAY TERMINAL 
    1. The ignition must be off when checking the resistance of a circuit.
    2. Before measuring the resistance of any circuit, first measure the resistance between the two leads of the DVOM. Note:  The meter leads can add resistance to the measurement value.
    3. Connect one lead of the DVOM to the circuit being tested at the relay terminal in the Power Distribution Center (PDC) Assembly.
    4. Connect the other lead to the circuit being tested at the Electronic Control Unit (ECU) harness connector and measure the resistance of the circuit.
      NOTE:

      When probing a circuit at any harness connector, always use an appropriate probing tool to prevent any possible damage to the harness connector terminals.

      Is the resistance above 3.0 Ohms?

      Yes 

      • Go To  7

      No 

      • Go To  9
  7. DISCONNECT THE PDC ASSEMBLY HARNESS CONNECTOR(S) AND CHECK THE (C902) WINDSHIELD HEATER RELAY CONTROL CIRCUIT FOR AN OPEN OR HIGH RESISTANCE 
    1. The ignition must be off when checking the resistance of a circuit.
    2. Isolate the circuit by disconnecting the Power Distribution Center (PDC) Assembly harness connector containing the circuit being tested. Note:  Use the wiring diagram as a guide to follow the path of the circuit.
    3. Before measuring the resistance of any circuit, first measure the resistance between the two leads of the DVOM. Note:  The meter leads can add resistance to the measurement value.
    4. Connect one lead of the DVOM to the circuit being tested at the PDC Assembly harness connector.
    5. Connect the other lead to the circuit being tested at the ECU harness connector and measure the resistance of the circuit.
      NOTE:

      When probing a circuit at any harness connector, always use an appropriate probing tool to prevent any possible damage to the harness connector terminals.

      Is the resistance above 3.0 Ohms?

      Yes 

      • Repair the circuit for an open or high resistance.
      • Perform the BODY VERIFICATION TEST. Refer to: BODY VERIFICATION TEST .

      No 

      • Go To  8
  8. DISCONNECT RELATED PDC ASSEMBLY HARNESS CONNECTIONS AND INSPECT FOR PROBLEMS 
    1. Disconnect all PDC Assembly harness connectors.
    2. Disconnect all related in-line harness connections (if equipped).
    3. Disconnect the related component harness connectors.
    4. Inspect harness connectors, component connectors, and all male and female terminals for the following conditions:
      • Proper connector installation.
      • Damaged connector locks.
      • Corrosion.
      • Other signs of water intrusion.
      • Weather seal damage (if equipped).
      • Bent terminals.
      • Overheating due to a poor connection (terminal may be discolored due to excessive current draw).
      • Terminals that have been pushed back into the connector cavity.
      • Perform a terminal drag test on each connector terminal to verify proper terminal tension.

      Repair any conditions that are found.

    5. Connect all PDC Assembly harness connectors. Be certain that all harness connectors are fully seated and the connector locks are fully engaged.
    6. Connect all in-line harness connectors (if equipped). Be certain that all connectors are fully seated and the connector locks are fully engaged.
    7. Connect all related component harness connectors. Be certain that all connectors are fully seated and the connector locks are fully engaged.
    8. With the scan tool, erase DTCs.
    9. Using the recorded Environmental Data, along with the When Monitored and Set Conditions above, operate the vehicle in the conditions that set the DTC.
    10. With the scan tool, read BCM DTCs.

      Did the DTC return?

      Yes 

      No 

  9. DISCONNECT RELATED BCM HARNESS CONNECTIONS AND INSPECT FOR PROBLEMS 
    1. Disconnect all BCM harness connectors.
    2. Disconnect all related in-line harness connections (if equipped).
    3. Disconnect the related component harness connectors.
    4. Inspect harness connectors, component connectors, and all male and female terminals for the following conditions:
      • Proper connector installation.
      • Damaged connector locks.
      • Corrosion.
      • Other signs of water intrusion.
      • Weather seal damage (if equipped).
      • Bent terminals.
      • Overheating due to a poor connection (terminal may be discolored due to excessive current draw).
      • Terminals that have been pushed back into the connector cavity.
      • Perform a terminal drag test on each connector terminal to verify proper terminal tension.

      Repair any conditions that are found.

    5. Connect all BCM harness connectors. Be certain that all harness connectors are fully seated and the connector locks are fully engaged.
    6. Connect all in-line harness connectors (if equipped). Be certain that all connectors are fully seated and the connector locks are fully engaged.
    7. Connect all related component harness connectors. Be certain that all connectors are fully seated and the connector locks are fully engaged.
    8. With the scan tool, erase DTCs.
    9. Using the recorded Environmental Data, along with the When Monitored and Set Conditions above, operate the vehicle in the conditions that set the DTC.
    10. With the scan tool, read BCM DTCs.

      Did the DTC return?

      Yes 

      No 

scientia non olet · About LEMON Manuals