No Response From HSM (Heated Seat Module)

NO RESPONSE FROM HSM (HEATED SEAT MODULE)

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









Diagnostic Test

1. CHECK IF THE MODULE IS ACTIVE ON THE BUS

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.

NOTE: Check the fuse for both the (F921) Fused Ignition Run circuit. If the fuse is open, make sure to check for a short to ground and repair as necessary before proceeding.

NOTE: Check the BCM for any active CAN DTCs and perform the appropriate diagnostics before proceeding. Testing and Inspection.

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

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

Yes

- Manufacturer Code Charts and perform the Stored Lost Communication DTCs diagnostic procedure.

No

- Go To 2

2. CHECK THE (F921) FUSED IGNITION RUN CIRCUIT FOR AN OPEN
1. Turn the ignition off.
2. Disconnect the Heated Seat Module C1 harness connector.
3. Ignition on, engine running.

NOTE: If equipped with Stop-Start, the engine may not run but the circuit should be powered up.

4. Using a 12-volt test light connected to ground, check the (F921) Fused Ignition Run circuit.

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?

Yes

- Go To 3

No

- Repair the (F921) Fused Ignition Run circuit for an open or high resistance.
- Perform the BODY VERIFICATION TEST. Body Verification Test .

3. CHECK THE (Z909) GROUND CIRCUIT FOR AN OPEN
1. Turn the ignition off.
2. Using a 12-volt test light connected to 12-volts, check the (Z909) Ground circuit.

Does the test light illuminate brightly?

Yes

- Go To 4

No

- Repair the (Z909) Ground circuit for an open or high resistance.
- Perform the BODY VERIFICATION TEST. Body Verification Test .

4. CHECK THE (D163) AND (D164) CAN INTERIOR BUS CIRCUITS FOR AN OPEN
1. Disconnect the Star Can IHS Body harness connector.
2. Measure the resistance of the (D164) CAN IHS Bus (-) circuit between the Star Can IHS Body harness connector and the Heated Seat Module C1 harness connector.
3. Measure the resistance of the (D163) CAN IHS Bus (+) circuit between the Star Can IHS Body 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 (D163) or (D164) CAN IHS Bus circuit for an open.
- Perform the BODY VERIFICATION TEST. Body Verification Test .