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. Apply the Horn switch.
3. With the scan tool, read 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 (X4) HORN RELAY CONTROL CIRCUIT FOR A SHORT TO GROUND

Fig 1: Checking Horn Relay Control Circuit For A Short To Ground
Courtesy of CHRYSLER GROUP, LLC
1. Turn the ignition off.
2. Disconnect the PDC C5 harness connector.
3. Disconnect the BCM A harness connector.
4. Measure the resistance between ground and the (X4) Horn Relay Control circuit.
  Is the resistance above 10k Ohms?
  
  Yes
  - Go To 3
  No
  - Repair the short to ground in the (X4) Horn Relay Control circuit.
  - Perform the BODY VERIFICATION TEST. Refer to STANDARD PROCEDURE .
CHECK THE BCM FOR CORRECT OPERATION
1. Turn the ignition off.
2. Reconnect the BCM A harness connector.
3. Using a 12-volt test light connected to ground, check the (X4) Horn Relay Control circuit at the PDC C5 harness connector.
4. Turn the ignition on.
5. Apply the Horn switch.
  Does the test light illuminate?
  
  Yes
  - Replace the PDC in accordance with the Service Information.
  - Perform the BODY VERIFICATION TEST. Refer to STANDARD PROCEDURE .
  No
  - Replace the Body Control Module (BCM) in accordance with the Service Information. Refer to MODULE, BODY CONTROL, REMOVAL .
  - Perform the BODY VERIFICATION TEST. Refer to STANDARD PROCEDURE .