Pinpoint Test O : The Left Heated Seat Is Inoperative -- With Heated/Ventilated Seats

WARNING: This page is about a different car, the 2020 Ford F-150. However, it is still accessible from the selected car via links, so may be relevant.

WARNING: Incorrect repair techniques or actions can cause an accidental Supplemental Restraint System (SRS) deployment. Never compromise or depart from these instructions. Failure to precisely follow all instructions could result in serious personal injury from an accidental deployment.

O1 CHECK FOR SCME (FRONT SEAT CLIMATE CONTROL MODULE) DIAGNOSTIC TROUBLE CODES (DTCS)

Ignition OFF.

Ignition ON.

Using a diagnostic scan tool, perform SCME self-test.

Are any SCME Diagnostic Trouble Codes (DTCs) present?

Yes	For DTC B1156:01, B1156:11, B1156:12, B1156:13 or B1156:1A, GO to O4 For DTC B1153:4B, B1208:01, B1208:11 or B1208:15, GO to O6 For all other Diagnostic Trouble Codes (DTCs), REFER to the DTC Chart: SCME .

GO to O2

O2 CHECK THE HEATED SEAT VOLTAGE SUPPLY CIRCUITS FOR AN OPEN

REFER to: Supplemental Restraint System (SRS) Depowering .

Disconnect: Driver Side Airbag In-line C3051.

Disconnect: DSM C341B.

Ignition ON.

Measure:

Positive Lead	Measurement / Action	Negative Lead
C341B-8	Courtesy of FORD MOTOR COMPANY	Ground
C341B-9	Courtesy of FORD MOTOR COMPANY	Ground

Are the voltages greater than 11 volts?

Yes

GO to O3

No	REPAIR the affected circuit. GO to O15

O3 CHECK THE HEATED SEAT GROUND CIRCUITS FOR AN OPEN

Ignition OFF.

Disconnect: DSM Module C341C.

Measure:

Positive Lead	Measurement / Action	Negative Lead
C341C-7	Courtesy of FORD MOTOR COMPANY	Ground
C341C-8	Courtesy of FORD MOTOR COMPANY	Ground

Are the resistances less than 3 ohms?

Yes

GO to O4

No	REPAIR the circuit in question. GO to O15

O4 CHECK THE HEATER ELEMENT POWER CIRCUIT FOR A SHORT TO VOLTAGE

REFER to: Supplemental Restraint System (SRS) Depowering .

Disconnect: Driver Side Airbag In-line C3051 (if not previously disconnected).

Disconnect: DSM C341A and C341B.

Disconnect: Left Front Seat Cushion Heater C3298.

Ignition ON.

Measure:

Positive Lead	Measurement / Action	Negative Lead
C3298-1	Courtesy of FORD MOTOR COMPANY	Ground

Is any voltage present?

Yes	REPAIR the circuit. GO to O15

GO to O5

O5 CHECK THE HEATER ELEMENT POWER CIRCUIT FOR AN OPEN OR SHORT TO GROUND

Ignition OFF.

Measure:

Positive Lead	Measurement / Action	Negative Lead
C3298-1	Courtesy of FORD MOTOR COMPANY	Ground

Measure:

Positive Lead	Measurement / Action	Negative Lead
C3298-1	Courtesy of FORD MOTOR COMPANY	C341B-2

Are the resistances greater than 10, 000 ohms between the driver seat cushion heater mat and ground; and less than 3 ohms between the driver seat cushion heater mat and the DSM?

Yes

GO to O9

No	REPAIR the affected circuit. GO to O15

O6 CHECK THE HEATED SEAT TEMPERATURE SENSOR CIRCUIT FOR AN OPEN OR SHORT TO GROUND

REFER to: Supplemental Restraint System (SRS) Depowering .

Disconnect: Driver Side Airbag In-line C3051.

Disconnect: DSM C341A and C341B.

Disconnect: Left Front Seat Cushion Heater C3298.

Measure:

Positive Lead	Measurement / Action	Negative Lead
C3298-2	Courtesy of FORD MOTOR COMPANY	Ground

Measure:

Positive Lead	Measurement / Action	Negative Lead
C3298-2	Courtesy of FORD MOTOR COMPANY	C341A-12

Is the resistance greater than 10, 000 ohms between the driver seat cushion heater mat and ground; and less than 3 ohms between the driver seat cushion heater mat and the DSM?

Yes

GO to O7

No	REPAIR the circuit. GO to O15

O7 CHECK THE HEATED SEAT TEMPERATURE SENSOR RETURN CIRCUIT FOR AN OPEN OR SHORT TO GROUND

Measure:

Positive Lead	Measurement / Action	Negative Lead
C3298-3	Courtesy of FORD MOTOR COMPANY	Ground

Measure:

Positive Lead	Measurement / Action	Negative Lead
C3298-3	Courtesy of FORD MOTOR COMPANY	C341A-9

Is the resistance greater than 10, 000 ohms between the driver seat cushion heater mat and ground; and less than 3 ohms between the driver seat cushion heater mat and the DSM?

Yes

GO to O8

No	REPAIR the open circuit or REFER to the OEM ELECTRICAL WIRING DIAGRAM INTRODUCTION to identify the possible causes of the circuit short. GO to O15

O8 CHECK THE HEATED SEAT TEMPERATURE SENSOR CIRCUIT FOR A SHORT TO VOLTAGE

Ignition ON.

Measure:

Positive Lead	Measurement / Action	Negative Lead
C3298-2	Courtesy of FORD MOTOR COMPANY	Ground

Is any voltage present?

Yes	REPAIR the circuit. GO to O15

GO to O13

O9 CHECK THE HEATER ELEMENT GROUND CIRCUIT FOR AN OPEN

Disconnect: Left Front Seat Backrest Heater C3590.

Measure:

Positive Lead	Measurement / Action	Negative Lead
C3590-2	Courtesy of FORD MOTOR COMPANY	C341B-4

Are the resistances less than 3 ohms?

Yes

GO to O10

No	REPAIR the circuit in question. GO to O15

O10 CHECK THE CUSHION HEATED SEAT MAT FOR AN OPEN OR SHORT TO GROUND

Measure the component side resistance between:

Positive Lead	Measurement / Action	Negative Lead
Courtesy of FORD MOTOR COMPANY C3298-1, Component Side	Courtesy of FORD MOTOR COMPANY	Courtesy of FORD MOTOR COMPANY C3298-4, Component Side
Courtesy of FORD MOTOR COMPANY C3298-1, Component Side	Courtesy of FORD MOTOR COMPANY	Ground

Is the resistance between 0.6 and 2 ohms between pins 1 and 4; and greater than 10, 000 ohms between pin 1 and ground?

Yes

GO to O11

No	INSTALL a new driver seat cushion heater mat. REFER to: Seat Heater Mat Removal . GO to O15

O11 CHECK THE BACKREST HEATED SEAT MAT FOR AN OPEN OR SHORT TO GROUND

Measure the component side resistance between:

Positive Lead	Measurement / Action	Negative Lead
Courtesy of FORD MOTOR COMPANY C3590-1, Component Side	Courtesy of FORD MOTOR COMPANY	Courtesy of FORD MOTOR COMPANY C3590-2, Component Side
Courtesy of FORD MOTOR COMPANY C3590-2, Component Side	Courtesy of FORD MOTOR COMPANY	Ground

Is the resistance between 0.6 and 2 ohms between pins 1 and 2; and greater than 10, 000 ohms between pin 2 and ground?

Yes

GO to O12

No	INSTALL a new driver seat backrest heater mat. REFER to: Seat Heater Mat Removal . GO to O15

O12 CHECK THE CIRCUIT BETWEEN THE CUSHION HEATER MAT AND BACKREST HEATER MAT FOR AN OPEN AND SHORT TO GROUND

Measure:

Positive Lead	Measurement / Action	Negative Lead
C3298-4	Courtesy of FORD MOTOR COMPANY	Ground

Measure:

Positive Lead	Measurement / Action	Negative Lead
C3298-4	Courtesy of FORD MOTOR COMPANY	C3590-1

Is the resistance greater than 10, 000 ohms between the driver seat cushion heater mat and ground; and less than 3 ohms between the driver seat cushion heater mat and the backrest heater mat?

Yes

GO to O14

No	REPAIR the circuit. GO to O15

O13 CHECK THE HEATED SEAT TEMPERATURE SENSOR FOR AN OPEN OR SHORT TO GROUND

Measure the component side resistance between:

Positive Lead	Measurement / Action	Negative Lead
Courtesy of FORD MOTOR COMPANY C3298-2, Component Side	Courtesy of FORD MOTOR COMPANY	Courtesy of FORD MOTOR COMPANY C3298-3, Component Side
Courtesy of FORD MOTOR COMPANY C3298-2, Component Side	Courtesy of FORD MOTOR COMPANY	Ground

Is the resistance between 300 and 300, 000 ohms between pins 2 and 3; and greater than 10, 000 ohms between pin 2 and ground?

Yes

GO to O14

No	INSTALL a new driver seat cushion heater mat. REFER to: Seat Heater Mat Removal . GO to O15

O14 CHECK THE SCME (FRONT SEAT CLIMATE CONTROL MODULE) OPERATION

Ignition OFF.

Disconnect and inspect all of the DSM connectors.

Repair:
- corrosion (install new connector or terminals - clean module pins)
- damaged or bent pins - install new terminals/pins as necessary
- pushed-out pins - install new pins as necessary

Reconnect the DSM connectors. Make sure they seat and latch correctly.

NOTE: Do not reconnect Driver Side Airbag In-line C3051 at this time.

Reconnect all previously disconnected connectors.

Ignition ON.

Operate the system and determine if the concern is still present.

Is the concern still present?

Yes	CHECK OASIS for any applicable Technical Service Bulletins (TSBs). If a TSB exists for this concern, DISCONTINUE this test and FOLLOW TSB instructions. If no Technical Service Bulletins (TSBs) address this concern, INSTALL a new SCME. REFER to: Driver Front Seat Module (DSM) . GO to O15

No	The system is operating correctly at this time. The concern may have been caused by module connections. ADDRESS the root cause of any connector or pin issues. GO to O15

O15 VERIFY THE SRS (SUPPLEMENTAL RESTRAINT SYSTEM) PROVES OUT SUCCESSFULLY

REFER to: Supplemental Restraint System (SRS) Depowering .

Connect: Driver Side Airbag In-line C3051.

Connect all previously disconnected connectors.

REFER to: Supplemental Restraint System (SRS) Repowering .

Did the SRS prove out successfully?

Yes	Repair is complete. RETURN the vehicle to the customer.

No	For Raptor and Phantom, REFER to: Airbag Supplemental Restraint System (SRS) . For all except Raptor and Phantom, REFER to: Airbag Supplemental Restraint System (SRS) .