Pinpoint Test B : The LH (Left-Hand) Heated Rear Seat Is Inoperative

WARNING: This page is about a different car, the 2018 Ford Edge. 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.

B1 CHECK THE HEATED SEAT SWITCH INPUT

Ignition OFF.

Disconnect Heated Rear Seat Module C3304A.

While pressing and releasing the LH heated rear seat switch, measure:

Positive Lead	Measurement / Action	Negative Lead
C3304A-2	Courtesy of FORD MOTOR COMPANY	Ground

Is the resistance less than 3 ohms when the switch is pressed and greater than 10, 000 ohms when released?

Yes

GO to B3

GO to B2

B2 CHECK THE HEATED SEAT SWITCH CIRCUIT FOR AN OPEN OR SHORT TO GROUND

Disconnect Heated Rear Seat Switch C3182.

Measure:

Positive Lead	Measurement / Action	Negative Lead
C3182-2	Courtesy of FORD MOTOR COMPANY	C3304A-2
C3182-2	Courtesy of FORD MOTOR COMPANY	Ground

Are the resistances less than 3 ohms between the heated seat switch and heated seat module, and greater than 10, 000 ohms between the heated seat switch and ground?

Yes	INSTALL a new heated rear seat switch. REFER to: Heated Rear Seat Switch .

No	REPAIR the circuit.

B3 CHECK FOR VOLTAGE TO THE HEATED SEAT MODULE

Disconnect Heated Rear Seat Module C3304B.

Measure:

Positive Lead	Measurement / Action	Negative Lead
C3304B-1	Courtesy of FORD MOTOR COMPANY	Ground

Is the voltage greater than 11 volts?

Yes

GO to B4

No	REPAIR the circuit.

B4 CHECK THE HEATER CIRCUITS AND HEATER MATS FOR AN OPEN

Measure:

Positive Lead	Measurement / Action	Negative Lead
C3304B-4	Courtesy of FORD MOTOR COMPANY	Ground

Is the resistance between 2.5 and 4.5 ohms?

Yes

GO to B9

GO to B5

B5 CHECK THE HEATER MAT GROUND CIRCUIT FOR AN OPEN

Disconnect LH Rear Backrest Heater Mat C3168.

Measure:

Positive Lead	Measurement / Action	Negative Lead
C3168-2	Courtesy of FORD MOTOR COMPANY	Ground

Is the resistance less than 3 ohms?

Yes

GO to B6

No	REPAIR the circuit.

B6 CHECK THE HEATER CIRCUIT FOR AN OPEN OR SHORT TO GROUND

Disconnect LH Rear Cushion Heater Mat C3167.

Measure:

Positive Lead	Measurement / Action	Negative Lead
C3304B-4	Courtesy of FORD MOTOR COMPANY	C3167-1

Measure:

Positive Lead	Measurement / Action	Negative Lead
C3304B-4	Courtesy of FORD MOTOR COMPANY	Ground

Are the resistances less than 3 ohms between the heated seat module and the LH rear cushion heater mat, and greater than 10, 000 ohms between the heated seat module and ground?

Yes

GO to B7

No	REPAIR the circuit.

B7 CHECK THE CUSHION HEATER MAT FOR AN OPEN

Measure the component side resistance between:

Positive Lead	Measurement / Action	Negative Lead
Courtesy of FORD MOTOR COMPANY C3167-1, Component Side	Courtesy of FORD MOTOR COMPANY	Courtesy of FORD MOTOR COMPANY C3167-4, Component Side

Is the resistance between 1.5 and 2.5 ohms?

Yes

GO to B8

No	INSTALL a new cushion heater mat. REFER to: Seat Heater Mat Removal .

B8 CHECK FOR AN OPEN OR A SHORT TO GROUND BETWEEN THE HEATER MATS

Measure:

Positive Lead	Measurement / Action	Negative Lead
C3167-4	Courtesy of FORD MOTOR COMPANY	C3168-1

Measure:

Positive Lead	Measurement / Action	Negative Lead
C3167-4	Courtesy of FORD MOTOR COMPANY	Ground

Are the resistances less than 3 ohms between the cushion heater mat and backrest heater mat, and greater than 10, 000 ohms between cushion heater mat and ground?

Yes	INSTALL a new backrest heater mat. REFER to: Seat Heater Mat Removal .

No	REPAIR the circuit.

B9 CHECK THE TEMPERATURE SENSOR CIRCUIT FOR A SHORT TO VOLTAGE

If equipped with inflatable seat belts, REFER to: Supplemental Restraint System (SRS) Depowering .
- Disconnect: LH Second Row Safety Belt Inflator C3802.
- Disconnect: RH Second Row Safety Belt Inflator C3647.

Ignition ON.

Measure:

Positive Lead	Measurement / Action	Negative Lead
C3304A-3	Courtesy of FORD MOTOR COMPANY	Ground

Is any voltage present?

Yes	REPAIR the circuit. If equipped with inflatable seat belts, GO to B13

GO to B10

B10 CHECK THE TEMPERATURE SENSOR CIRCUIT FOR A SHORT TO GROUND

Ignition OFF.

Measure:

Positive Lead	Measurement / Action	Negative Lead
C3304A-3	Courtesy of FORD MOTOR COMPANY	Ground

Is the resistance greater than 10, 000 ohms?

Yes

GO to B11

No	REPAIR the circuit. If equipped with inflatable seat belts, GO to B13

B11 CHECK THE TEMPERATURE SENSOR AND CIRCUITS FOR AN OPEN

Measure:

Positive Lead	Measurement / Action	Negative Lead
C3304A-3	Courtesy of FORD MOTOR COMPANY	C3304A-12

Is the resistance between 300 and 300K ohms?

Yes	INSTALL a new heated rear seat module. REFER to: Heated Rear Seat Module . If equipped with inflatable seat belts, GO to B13

GO to B12

B12 CHECK THE TEMPERATURE SENSOR FOR AN OPEN WITH THE HEATER MAT DISCONNECTED

Disconnect LH Rear Cushion Heater Mat C3167.

Measure:

Positive Lead	Measurement / Action	Negative Lead
C3304A-3	Courtesy of FORD MOTOR COMPANY	C3167-2
C3304A-12	Courtesy of FORD MOTOR COMPANY	C3167-3

Are the resistances less than 3 ohms?

Yes	INSTALL a new cushion heater mat. REFER to: Seat Heater Mat Removal . If equipped with inflatable seat belts, GO to B13

No	REPAIR the circuit in question. If equipped with inflatable seat belts, GO to B13

B13 VERIFY THE SRS (SUPPLEMENTAL RESTRAINT SYSTEM) PROVES OUT SUCCESSFULLY
- REFER to: Supplemental Restraint System (SRS) Depowering .
- Connect: LH Second Row Safety Belt Inflator C3802.
- Connect: RH Second Row Safety Belt Inflator C3647.
- 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 REFER to: Airbag Supplemental Restraint System (SRS) .