Pinpoint Test D: The Power Lumbar Is Inoperative -- Driver, Without Multi-Contour Seats

WARNING: This page is about a different car, the 2021 Ford F-150. However, it is still accessible from the selected car via links, so may be relevant.

Refer to Wiring Diagrams POWER SEATS for schematic and connector information.
Normal Operation and Fault Conditions

REFER to: Front Seats - System Operation and Component Description .

Possible Sources
- Wiring, terminals or connectors
- Seat control switch
- Front seat power lumbar assembly
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.

D1 CHECK FOR VOLTAGE TO THE SEAT LUMBAR MOTOR

REFER to: Supplemental Restraint System (SRS) Depowering .

Disconnect: Driver Side Airbag In-line C3051.

Disconnect: Driver Seat Lumbar Motor C3215.

NOTE: The voltage being measured changes polarity depending upon which direction the seat control switch is activated.

While pushing the lumbar switch in both directions, measure:

Positive Lead	Measurement / Action	Negative Lead
C3215-A	Courtesy of FORD MOTOR COMPANY	C3215-B

Is the voltage greater than 11 volts when the seat control switch is operated in both directions?

Yes	INSTALL a new driver seat power lumbar assembly. REFER to: Front Seat Power Lumbar Assembly - Vehicles Without: Multi-Contour Seats . GO to D3

GO to D2

D2 CHECK THE SEAT LUMBAR MOTOR CIRCUITS FOR AN OPEN

Disconnect: Driver Seat Control Switch C360 (8-way seat) or C3387 (10-way seat).

If equipped with 8-way seat, measure:

Positive Lead	Measurement / Action	Negative Lead
C360-4	Courtesy of FORD MOTOR COMPANY	C3215-B
C360-3	Courtesy of FORD MOTOR COMPANY	C3215-A

If equipped with 10-way seat, measure:

Positive Lead	Measurement / Action	Negative Lead
C3387-2	Courtesy of FORD MOTOR COMPANY	C3215-B
C3387-6	Courtesy of FORD MOTOR COMPANY	C3215-A

Are the resistances less than 3 ohms?

Yes	INSTALL a new driver seat control switch. REFER to: Front Seat Control Switch . GO to D3

No	REPAIR the circuit in question. GO to D3

D3 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 REFER to: Airbag Supplemental Restraint System (SRS) .