Front Heated Seat Inoperative/Cold (Install Seat Heat Element)

Some customers may comment that the front seat assembly heat function is not operating properly. The front seat back and seat cushion remain cold when the HEAT/OFF switch is activated.

This condition may be due to a non-functioning heat element in the front heated seat back/cushion trim cover. The heated seat system consists of the two front heated seats.

1. Determine which heat element is not functioning properly by measuring the resistance values of the factory heat elements. Refer to the diagnostic procedure in this bulletin.
2. If the resistance values of a factory heat element are NOT within the specified range, install a service heat element between the non-functioning factory heat element and the seat trim cover. Refer to Service Heat Element Installation in this bulletin.

1. Adjust the front seat assembly to the maximum up and rearward position in order to access the heated seat control module electrical connector.



2. Disconnect the heated seat control module harness gray, 6-way connector C2.
3. Measure the front seat heat element total resistance between cavities A and C. Does the resistance measure less than 5 ohms?

•	If yes, go to Step 4.

•	If no, go to Step 5 in order to determine which of the three seat heat elements has a resistance value NOT within the specified range.

Important: If the resistance is measured with the seat still warm, the resistance may vary outside of the specified range since the thermistor resistance varies with temperature.

4. Measure the front seat heat element thermistor resistance between cavities D and F. Does the resistance measure between 850 ohms and 11.5 K ohms ?

•	If yes, the resistance values of the heat elements are within the specified range. To find the cause of the inoperative/cold heated seat, perform the standard diagnostic procedures in the Service Manual.

•	If no, install a front seat cushion center heat element. Refer to Service Heat Element Installation in this bulletin.

5. Remove the front seat cushion. Refer to Seat Cushion Replacement-Front in the Seats sub-section of the Service Manual or SI document #730654.



6. Disconnect the seat cushion heater extension white, 2-way connector from the seat cushion center heater harness.
7. Measure the seat cushion extension heat element resistance between cavities A and B at the white 2-way connector. Does the resistance measure less than 5 ohms?

•	If yes, go to Step 8.

•	If no, install a front seat cushion extension heat element. Refer to Service Heat Element Installation in this bulletin.

8. Measure the seat back heat element resistance between cavities A and B at the white 2-way connector. Does the resistance measure less than 5 ohms?

•	If yes, install a front seat cushion center heat element. Refer to Service Heat Element Installation in this bulletin.

•	If no, install a front seat back heat element. Refer to Service Heat Element Installation in this bulletin.

If a sublet trim repair facility is used, please provide a copy of this bulletin to the repair shop.

Important: Before installing the service heat element to the seat trim cover, verify that the resistance values are within the specified range. Refer to the following table:

Important: DO NOT attempt to remove the factory heat elements from the seat trim cover. The service heat element is to be installed between the existing factory heat element and the seat trim cover.

1. Remove the front seat cushion trim cover. Refer to Seat Cushion Cover and Pad Replacement-Front in the Seats sub-section of the Service Manual or SI document #730658.
2. Place the seat trim cover on a clean flat surface with the inside facing out.
3. Remove the wiring harness from ONLY the non-functioning factory heat element. Use a pair of diagonal side cutters to cut the wiring as close to the factory heat element material as possible.




Important: DO NOT start the cut with a jab or poke.

4. Create an opening between the non-functioning factory heat element (1) and the seat trim cover as close to the seam (2) as possible. Use a razor blade or an equivalent sharp tool and carefully slice through the factory heat element until a hole is created.

4.1.	Insert your finger(s) through the hole and lift the heat material (1) away from the trim cover material.

4.2.	Use scissors and/or a razor blade to cut the factory heat element material along the entire length of the seam (2) from corner to corner.




5. With the backing paper side to the factory heat element material, insert the service heat element (3) between the trim cover material and the factory heat element material (4).

•	Ensure the service heat element is laying flat, is tucked into each corner and extends to each side.

•	Carefully remove the backing paper from the service heat element.

6. Use 3M® Highland Cloth Duct Tape, P/N 06969, or equivalent, to cover the seam opening.
7. Connect the seat cushion extension heat element 2-way white connector to the seat cushion center heat element harness.
8. Install the front seat cushion trim cover. Refer to Seat Cushion Cover and Pad Replacement-Front in the Seats sub-section of the Service Manual or SI document #730658.
9. Install the front seat cushion. Refer to Seat Cushion Replacement-Front in the Seats sub-section of the Service Manual or SI document #730654.
10. Verify the seat heat function is operational.

Parts are currently available from GMSPO.

For vehicles repaired under warranty, use: