Diagnostic Test

WARNING: This page is about a different car, the 2012 RAM Pickup and 2012 RAM Cab & Chassis. However, it is still accessible from the selected car via links, so may be relevant.

TEST FOR INTERMITTENT CONDITION
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).
3. Turn the ignition off.
4. Start the engine and let it run.
5. Using a scan tool, read DTCs.
  Is the DTC active?
  
  Yes
  - Go To 2.
  No
  - The conditions that caused this code to set are not present at this time. Verify seat harness is routed correctly to the HSM. Using the wiring diagram/schematic as a guide, inspect the wiring and connectors. Look for chafed, pierced, pinched, or partially broken wires and broken, bent, pushed out, spread, corroded, or contaminated terminals. Attempt to reproduce condition by operating all HSM functions one at a time, except for the Left Rear Heated Seat. Attempt to reproduce condition by adjusting the front seat.
  - Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .
CHECK (P177) LEFT REAR SEAT HEATER CONTROL CIRCUIT FOR A SHORT TO VOLTAGE

Fig 1: Checking Left Rear Seat Heater Control Circuit For A Short To Voltage
Courtesy of CHRYSLER GROUP, LLC
1. Turn the ignition off.
2. Disconnect the HSM C3 harness connector.
  NOTE:
  Check connectors. Clean and repair as necessary.
3. Start the engine and let it run.
4. Measure the voltage of the (P177) Left Rear Seat Heater Control circuit between the HSM C3 harness connector and ground.
  Is there any voltage present?
  
  Yes
  - Go To 3.
  No
  - Go To 4.
CHECK (P177) LEFT REAR SEAT HEATER CONTROL CIRCUIT FOR A SHORT TO THE (F931) FUSED IGNITION RUN CONTROL OUTPUT CIRCUIT

Fig 2: Checking Left Rear Seat Heater Control Circuit For A Short To The Fused Ignition Run Control Output
Courtesy of CHRYSLER GROUP, LLC
1. Turn the ignition off.
2. Measure the resistance between the (P177) Left Rear Seat Heater Control circuit and the (F931) Fused Ignition Run Control Output circuit at HSM C3 harness connector.
  Is the resistance below 10K Ohms?
  
  Yes
  - Repair the (P177) Left Rear Seat Heater Control circuit for a short to the (F931) Fused Ignition Run Control Output circuit.
  - Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .
  No
  - Repair the (P177) Left Rear Seat Heater Control circuit for a short to voltage.
  - Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .
CHECK (P177) LEFT REAR SEAT HEATER CONTROL CIRCUIT FOR A SHORT TO VOLTAGE DURING SEAT ADJUSTMENT

Fig 3: Checking Left Rear Seat Heater Control Circuit For A Short To Voltage
Courtesy of CHRYSLER GROUP, LLC
1. Measure the Voltage of the (P177) Left Rear Seat Heater Control circuit between the HSM C3 harness connector and ground while adjusting the left front seat.
  Is there any Voltage present during the seat adjustment?
  
  Yes
  - Repair the (P177) Left Rear Seat Heater Control circuit for a short to voltage.
  - Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .
  No
  - Go To 5.
CHECK (P177) LEFT REAR SEAT HEATER CONTROL CIRCUIT FOR A SHORT TO THE (P178) RIGHT REAR SEAT HEATER CONTROL CIRCUIT

Fig 4: Checking Left Rear Seat Heater Control Circuit For Short To Right Rear Heater Control Circuit
Courtesy of CHRYSLER GROUP, LLC
1. Turn the ignition off.
2. Disconnect the Left or Right Rear Seat Cushion Heater harness connector.
3. Measure the resistance between the (P177) Left Rear Seat Heater Control circuit and the (P178) Right Rear Seat Heater Control circuit at HSM C3 harness connector.
  Is the resistance below 10K Ohms?
  
  Yes
  - Repair the (P177) Left Rear Seat Heater Control circuit for a short to the (P178) Right Rear Seat Heater Control circuit.
  - Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .
  No
  - Replace the Heated Seat Module (HSM) in accordance with the Service Information.
  - Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .