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 IF THE DTC IS ACTIVE
NOTE:
Make sure the battery is fully charged and the charging system is operating properly before proceeding.
1. Turn the ignition on.
2. Using a scan tool, record and erase Diagnostic Trouble Codes (DTCs).
  NOTE:
  It is recommended to record any Environmental Data to help identify the conditions in which the DTC was set.
3. Turn the ignition off.
4. Ignition on, engine running.
5. Turn the Vented Seat on and wait at least 12 seconds before proceeding.
6. With the scan tool, read Heated Seat Module (HSM) DTCs.
  Does the scan tool show this DTC as active?
  
  Yes
  - Go To 2
  No
  - Go To 6
CHECK THE (P421) LEFT SEAT VENT FEED CIRCUIT FOR AN OPEN
1. Turn the ignition off.
2. Disconnect the HSM C5 harness connector.
3. Disconnect the Left Seat Cushion Vent Motor.
4. Disconnect the Left Seat Back Vent Motor.
5. Connect a fused jumper wire between B(+) and the (P421) Left Seat Vent Feed circuit in the HSM C5 harness connector.
6. Using a 12 volt test light connected to ground, check the (P421) Left Seat Vent Feed circuit at the Left Seat Cushion Vent Motor and the Left Seat Back Vent Motor harness connectors.
  NOTE:
  The test light must illuminate brightly. Compare the brightness to that of a direct connection to the battery.
  
  Does the test light illuminate brightly at both harness connectors?
  
  Yes
  - Go To 3
  No
  - Repair the (P421) Left Seat Vent Feed circuit for an open.
  - Perform the BODY VERIFICATION TEST. Refer to STANDARD PROCEDURE .
CHECK THE (P921) LEFT SEAT RETURN CIRCUIT FOR AN OPEN
1. Disconnect the fused jumper wire between B(+) and the (P421) Left Seat Vent Feed circuit in the HSM C5 harness connector.
2. Connect the fused jumper wire between B(+) and the (P921) Left Seat Vent Return circuit in the HSM C5 harness connector.
3. Using a 12 volt test light connected to ground, check the (P921) Left Seat Vent Return circuit at the Left Seat Cushion Vent Motor and the Left Seat Back Vent Motor harness connectors.
  Does the test light illuminate brightly at both harness connectors?
  
  Yes
  - Go To 4
  No
  - Repair the (P921) Left Seat Vent Return circuit for an open.
  - Perform the BODY VERIFICATION TEST. Refer to STANDARD PROCEDURE .
CHECK THE LEFT SEAT CUSHION VENT MOTOR
1. Disconnect the fused jumper wire between B(+) and the (P921) Left Seat Vent Return circuit in the HSM C5 harness connector.
2. Connect a fused jumper wire between B(+) and the (P421) Left Seat Vent Feed circuit in the Left Cushion Vent Motor connector.
3. Measure the amperage by connecting an ammeter between ground and the (P921) Left Seat Vent Return circuit in the Left Cushion Vent Motor connector.
  NOTE:
  Individual vent motors normally operate between 400 and 500 mA.
  
  Is the amperage between 300 and 700 mA?
  
  Yes
  - Go To 5
  No
  - Replace the Seat Cushion Vent Motor in accordance with the Service Information. Refer to MOTOR, VENTED SEAT, REMOVAL .
  - Perform the BODY VERIFICATION TEST. Refer to STANDARD PROCEDURE .
CHECK THE LEFT SEAT BACK VENT MOTOR
1. Disconnect the fused jumper wire between B(+) and the (P421) Left Seat Vent Feed circuit in the Left Cushion Vent Motor connector.
2. Connect a fused jumper wire between B(+) and the (P421) Left Seat Vent Feed circuit in the Left Back Vent Motor connector.
3. Measure the amperage by connecting an ammeter between ground and the (P921) Left Seat Vent Return circuit in the Left Back Vent Motor connector.
  Is the amperage between 300 and 700 mA?
  
  Yes
  - Replace the Heated Seat Module (HSM) in accordance with the Service Information. Refer to MODULE, HEATED SEAT, REMOVAL .
  - Perform the BODY VERIFICATION TEST. Refer to STANDARD PROCEDURE .
  No
  - Replace the Seat Back Vent Motor in accordance with the Service Information. Refer to MOTOR, VENTED SEAT, REMOVAL .
  - Perform the BODY VERIFICATION TEST. Refer to STANDARD PROCEDURE .
CHECK THE WIRING AND CONNECTORS
1. The conditions necessary to set the DTC are not present at this time.
2. Using the schematics as a guide, inspect the wiring and connectors specific to this circuit. Wiggle the wiring and connectors while checking for shorted and open circuits. Attempt to reproduce the condition by adjusting the seat(s).
3. Check all related splices and connectors for signs of water intrusion, corrosion, pushed out or bent terminals, and correct pin tension. Verify the seat wiring harness is routed correctly to the Heated Seat Module (HSM).
4. With the scan tool, check for any Environmental Data to help identify the conditions in which the DTC was set.
5. Check Service Bulletins for any possible causes that may apply.
  Were there any problems found?
  
  Yes
  - Repair as necessary.
  - Perform the BODY VERIFICATION TEST. Refer to STANDARD PROCEDURE .
  No
  - Test complete.