Diagnostic Test

WARNING: This page is about a different car, the 2017 RAM 2500 HD. However, it is still accessible from the selected car via links, so may be relevant.

CHECK FOR AN ACTIVE DTC
1. With the scan tool, read DTCs and record on the repair order.
2. Record the Environmental Data.
3. With the scan tool, erase DTCs.
4. Start the engine.
5. Turn the Left Front Vented Seat on.
6. With the scan tool, read HSM DTCs.
  Is the same DTC active?
  
  Yes
  - Go To 2
  No
  - Perform the TESTING FOR AN INTERMITTENT CONDITION procedure. Refer to TESTING FOR AN INTERMITTENT CONDITION .
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 BODY VERIFICATION TEST .
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 BODY VERIFICATION TEST .
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 BODY VERIFICATION TEST .
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
  - Go To 6
  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 BODY VERIFICATION TEST .
CHECK RELATED HARNESS CONNECTIONS
1. Disconnect all HSM 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.
  - Check for spread terminals and verify proper terminal tension.
  Repair any conditions that are found.
5. Connect all HSM 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. Test drive or operate the vehicle in accordance with the when monitored and set conditions.
10. With the scan tool, read HSM DTCs.
  Is the same DTC active?
  
  Yes
  - Replace the Heated Seat Module (HSM) in accordance with the Service Information. Refer to MODULE, HEATED SEAT (HSM), REMOVAL .
  - Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .
  No
  - Repairing the wiring harness or connections corrected the problem.
  - Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .