PINPOINT TEST C : Power-Stow Seat Motor and Sensor Functional Test - LH

NOTE: Verify good battery condition before diagnosing the PFSM system. Poor battery condition may interfere with PFSM operation. If battery voltage drops below 10 volts, seat movement will not start. If battery voltage drops below 8 volts, a started seat movement will stop.

NOTE: The battery saver relay system will time-out after 10 minutes and disable the third row power seat operation. Meter voltage measurements will be inaccurate when this occurs, which could lead to misdiagnosis. To enable the battery saver relay system during diagnosis and testing, close and open any vehicle door.

NOTE: The following pinpoint test uses a test light to simulate normal circuit loads. Use only the test light recommended in the Special Tools table at the beginning of this article. To avoid connector terminal damage, use the Flex Probe Kit for the test light probe connection to the vehicle. Do not use the test light probe directly on any connector.

C1 CHECK THE PFSM FOR OUTPUT VOLTAGE TO THE POWER-STOW SEAT MOTOR

Access the PFSM. To access the PFSM, Refer to Power-Fold Seat Module (PFSM) .

NOTE: Before moving the seat, make sure all parts are out from under it or damage can occur.

Reposition the PFSM and wiring away from the seat so that the seat can be moved during testing without damaging the PFSM or wire harness.

Detach the PFSM and wire harness completely from the LH load floor flapper panel.

Lower the PFSM and wire harness to the floor in front of the seat.

Before the seat is moved, make sure the wiring is clear from the pivot areas of the seat and cannot be pinched or torn by seat movement.

Verify the vehicle is in PARK and the liftgate is open.

Verify the courtesy lights are on. If needed, close and open any door on the vehicle.

NOTE: This pinpoint test step directs testing circuits using a back-probe method. Use the special back-probe tool specified in the tool list in this article. Do not force test leads or other probes into connectors. Adequate care must be exercised to avoid connector terminal damage while making sure that good electrical contact is made with the circuit or terminal. Failure to follow these instructions may cause damage to wiring, terminals, or connectors and subsequent electrical faults.

Measure:

Positive Lead	Measurement / Action	Negative Lead
PFSM C4250C-12	Test Light	PFSM C4250C-10

Press the STOW button and monitor the test light.

Does the test light illuminate momentarily when the STOW button is pressed?

Yes	GO to C4.
No	GO to C2.

C2 CHECK THE LH POWER-STOW SEAT MOTOR AND CIRCUITS FOR A SHORT TO GROUND

Disconnect: PFSM C4250C .

Measure:

Positive Lead	Measurement / Action	Negative Lead
C4250C-12	Courtesy of FORD MOTOR COMPANY	Ground
C4250C-10	Courtesy of FORD MOTOR COMPANY	Ground

Are the resistances greater than 10, 000 ohms?

Yes	GO to C10.
No	GO to C3.

C3 CHECK THE LH POWER-STOW SEAT MOTOR AND CIRCUITS FOR A SHORT TO GROUND

Disconnect: LH Power-Stow Seat Motor.
- Remove the rear quarter trim finish panel to access the LH power-stow seat motor electrical connector. REFER to Interior Trim and Ornamentation - With Inflatable Safety Belts or REFER to Interior Trim and Ornamentation - Without Inflatable Safety Belts. .

Measure:

Positive Lead	Measurement / Action	Negative Lead
C4250C-12	Courtesy of FORD MOTOR COMPANY	Ground
C4250C-10	Courtesy of FORD MOTOR COMPANY	Ground

Are the resistances greater than 10, 000 ohms?

Yes	INSTALL a new LH power-stow seat motor. Refer to Power-Stow Seat Motor .
No	REPAIR the affected circuit(s).

C4 CHECK THE LH POWER-STOW SEAT MOTOR AND CIRCUITS FOR AN OPEN

Disconnect: PFSM C4250C .

Measure:

Positive Lead	Measurement / Action	Negative Lead
C4250C-12	Courtesy of FORD MOTOR COMPANY	C4250C-10

Is the resistance less than 3 ohms?

Yes	GO to C6.
No	GO to C5.

C5 CHECK THE LH POWER-STOW SEAT MOTOR CIRCUITS FOR AN OPEN

Disconnect: LH Power-Stow Seat Motor.
- Remove the rear quarter trim finish panel to access the LH power-stow seat motor electrical connector. REFER to Interior Trim and Ornamentation - With Inflatable Safety Belts or REFER to Interior Trim and Ornamentation - Without Inflatable Safety Belts. .

Measure:

Positive Lead	Measurement / Action	Negative Lead
C4250C-12	Courtesy of FORD MOTOR COMPANY	C4181-3
C4250C-10	Courtesy of FORD MOTOR COMPANY	C4181-1

Are the resistances less than 3 ohms?

Yes	INSTALL a new LH power-stow seat motor. Refer to Power-Stow Seat Motor .
No	REPAIR the affected circuit(s).

C6 CHECK THE PFSM FOR OUTPUT VOLTAGE TO THE STOW SENSOR

Connect: PFSM C4250C .

Verify the vehicle is in PARK and the liftgate is open.

Verify the courtesy lights are on. If needed, close and open any door on the vehicle.

Measure:

Positive Lead	Measurement / Action	Negative Lead
PFSM C4250C-2	Courtesy of FORD MOTOR COMPANY	PFSM C4250C-5

Is the voltage greater than 5 volts?

Yes	GO to C9.
No	GO to C7.

C7 CHECK THE LH POWER-STOW SEAT MOTOR SENSOR AND CIRCUIT FOR A SHORT TO GROUND

Disconnect: PFSM C4250C .

Measure:

Positive Lead	Measurement / Action	Negative Lead
C4250C-2	Courtesy of FORD MOTOR COMPANY	Ground

Is the resistance greater than 10, 000 ohms?

Yes	GO to C10.
No	GO to C8.

C8 CHECK THE LH POWER-STOW SEAT MOTOR SENSOR CIRCUITS FOR A SHORT TO GROUND

Disconnect: LH Power-Stow Seat Motor.
- Remove the rear quarter trim finish panel to access the LH power-stow seat motor electrical connector. REFER to Interior Trim and Ornamentation - With Inflatable Safety Belts or REFER to Interior Trim and Ornamentation - Without Inflatable Safety Belts. .

Measure:

Positive Lead	Measurement / Action	Negative Lead
C4250C-2	Courtesy of FORD MOTOR COMPANY	Ground
C4250C-5	Courtesy of FORD MOTOR COMPANY	Ground

Are the resistances greater than 10, 000 ohms?

Yes	INSTALL a new LH power-stow seat motor. Refer to Power-Stow Seat Motor .
No	REPAIR the affected circuit.

C9 CHECK THE LH POWER-STOW SEAT MOTOR SENSOR CIRCUITS FOR AN OPEN

Disconnect: LH Power-Stow Seat Motor.
- Remove the rear quarter trim finish panel to access the LH power-stow seat motor electrical connector. REFER to Interior Trim and Ornamentation - With Inflatable Safety Belts or REFER to Interior Trim and Ornamentation - Without Inflatable Safety Belts. .

Disconnect: PFSM C4250C .

Measure:

Positive Lead	Measurement / Action	Negative Lead
C4250C-2	Courtesy of FORD MOTOR COMPANY	C4181-2
C4250C-5	Courtesy of FORD MOTOR COMPANY	C4181-4

Are the resistances less than 3 ohms?

Yes	INSTALL a new LH power-stow seat motor. Refer to Power-Stow Seat Motor .
No	REPAIR the affected circuit(s).

C10 CHECK PFSM CONNECTORS AND PINS FOR DAMAGE AND RETEST THE SYSTEM

Disconnect and inspect all PFSM 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 all previously disconnected electrical connectors.

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

Is the concern still present?

Yes	CHECK OASIS for any applicable TSBs. If a TSB exists for this concern, DISCONTINUE this test and FOLLOW TSB instructions. If no TSBs address this concern, INSTALL a new PFSM. Refer to Power-Fold Seat Module (PFSM) .
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.