No Response From HSM (Heated Seat Module)

NO RESPONSE FROM HSM (HEATED SEAT MODULE)

For a complete wiring diagram, refer to the Wiring Information.






1. TEST FOR INTERMITTENT CONDITION

NOTE: Check for any TSB(s) related to the condition. If a TSB applies, perform the procedure outlined in the TSB before continuing.

1. Turn the ignition on.

NOTE: Make sure the battery voltage is between 10.0 and 16.0 volts.

2. With the scan tool, read the module status.

NOTE: Check the BCM for any active CAN hardware DTCs, perform DTC before proceeding.

Does the scan tool indicate that the module is active on the bus?

Yes

- The no response condition is not present at this time. Using the wiring diagram/schematic as a guide, inspect the wiring for chafed, pierced, pinched, and partially broken wires and the wiring harness connectors for broken, bent, pushed out, and corroded terminals.
- Perform the BODY VERIFICATION TEST. Body Verification Test.

No

- Go To 2

2. CHECK THE (F921) FUSED IGNITION RUN RELAY OUTPUT CIRCUIT FOR AN OPEN OR SHORT




1. Turn the ignition off.
2. Disconnect the Heated Seat Module C1 harness connector.
3. Turn the ignition on.
4. Using a 12-volt test light connected to ground, check the (F921) Fused Ignition Run Relay Output circuit.

Does the test light illuminate brightly?

Yes

- Go To 3

No

- Repair the open or short in the (F921) Fused Ignition Run Relay Output circuit.
- Perform the BODY VERIFICATION TEST. Body Verification Test.

3. CHECK THE (Z921) GROUND CIRCUIT FOR AN OPEN




1. Turn the ignition off.
2. Using a 12-volt test light connected to 12-volts, check the (Z921) Ground circuit.

Does the test light illuminate brightly?

Yes

- Go To 4

No

- Repair the open in the (Z921) Ground circuit.
- Perform the BODY VERIFICATION TEST. Body Verification Test.

4. CHECK THE (D163) AND (D164) CAN IHS BUS (125K) CIRCUITS FOR AN OPEN
1. Disconnect the Front CAN IHS Star Connector C3 harness connector.
2. Measure the resistance of the (D164) CAN IHS Bus (125K) (-) circuit between the Front CAN IHS Star Connector C3 harness connector and the Heated Seat Module C1 harness connector.
3. Measure the resistance of the (D163) CAN IHS Bus (125K) (+) circuit between the Front CAN IHS Star Connector C3 harness connector and the Heated Seat Module C1 harness connector.

Are the resistances below 5.0 Ohms?

Yes

- Replace the Heated Seat Module. Heated Seat Module - Removal.
- Perform the BODY VERIFICATION TEST. Body Verification Test.

No

- Repair the open in the (D163) or (D164) CAN IHS Bus (125K) circuit.
- Perform the BODY VERIFICATION TEST. Body Verification Test.