Diagnostic Test

WARNING: This page is about a different car, the 2013 RAM 3500 HD and 2013 RAM 2500 HD. However, it is still accessible from the selected car via links, so may be relevant.

CHECK FOR AN ACTIVE DTC
1. Turn the ignition on.
2. Turn the Headlamps on.
3. With the scan tool, read the DTCs.
  Does the scan tool display this DTC as active?
  
  Yes
  - Go To 2
  No
  - Test complete. The condition or conditions that originally set this DTC are not present at this time. Using the wiring diagrams as a guide, check all related splices and connectors for signs of water intrusion, corrosion, pushed out or bent terminals and correct pin tension.
  - Perform the BODY VERIFICATION TEST. Refer to STANDARD PROCEDURE .
CHECK THE (L307) HEADLAMP SWITCH MUX CIRCUIT FOR A SHORT TO VOLTAGE
1. Turn the ignition off.
2. Disconnect the Headlamp Switch harness connector.
3. Turn the ignition on.
4. Measure the voltage of the (L307) Headlamp Switch MUX circuit.
  Is the voltage above 5.0 volts?
  
  Yes
  - Repair the (L307) Headlamp Switch MUX circuit for a short to voltage.
  - Perform the BODY VERIFICATION TEST. Refer to STANDARD PROCEDURE .
  No
  - Go To 3
HEADLAMP SWITCH
1. Turn the ignition off.
2. Connect a jumper wire between ground and the (L307) Headlamp Switch MUX circuit at the Headlamp Switch harness connector.
3. Turn the ignition on.
4. With the scan tool, read the DTCs.
  Does the scan tool display DTC: B178E-11-HEADLAMP SWITCH INPUT - CIRCUIT SHORT TO GROUND?
  
  Yes
  - Replace the Headlamp Switch in accordance with the Service Information. Refer to SWITCH, HEADLAMP, REMOVAL .
  - Perform the BODY VERIFICATION TEST. Refer to STANDARD PROCEDURE .
  No
  - Go To 4
CHECK THE (L307) HEADLAMP SWITCH MUX CIRCUIT FOR AN OPEN
1. Turn the ignition off.
2. Disconnect the BCM G harness connector.
3. Measure the resistance of the (L307) Headlamp Switch MUX circuit.
  Is the resistance below 5.0 Ohms?
  
  Yes
  - Go To 5
  No
  - Repair the (L307) Headlamp Switch MUX circuit for an open.
  - Perform the BODY VERIFICATION TEST. Refer to STANDARD PROCEDURE .
CHECK THE (L900) HEADLAMP SWITCH MUX RETURN CIRCUIT FOR AN OPEN
1. Measure the resistance of the (L900) Headlamp Switch MUX Return circuit.
  Is the resistance below 5.0 Ohms?
  
  Yes
  - Replace the BCM in accordance with the Service Information. Refer to MODULE, BODY CONTROL, REMOVAL .
  - Perform the BODY VERIFICATION TEST. Refer to STANDARD PROCEDURE .
  No
  - Repair the (L307) Headlamp Switch MUX Return circuit for an open.
  - Perform the BODY VERIFICATION TEST. Refer to STANDARD PROCEDURE .