Pinpoint Test B : P0645, P0646, P0647

WARNING: This page is about a different car, the 2018 Ford F-550 Super Duty, 2018 Ford F-450 Super Duty, 2018 Ford F-350 Super Duty, and 2018 Ford F-250 Super Duty. However, it is still accessible from the selected car via links, so may be relevant.

NOTE: Use the correct probe adapter(s) from the Flex Probe Kit when taking measurements. Failure to use the correct probe adapter(s) may damage the connector.

B1 CHECK THE VOLTAGE TO THE A/C (AIR CONDITIONING) CLUTCH RELAY VOLTAGE SUPPLY CIRCUIT

Ignition OFF.

Disconnect A/C clutch relay.

Ignition ON.

Measure:

Positive Lead	Measurement / Action	Negative Lead
A/C clutch relay socket 1	Courtesy of FORD MOTOR COMPANY	Ground

Positive Lead	Measurement / Action	Negative Lead
A/C clutch relay socket 3	Courtesy of FORD MOTOR COMPANY	Ground

Are the voltages greater than 11 volts?

Yes

GO to B2

No	VERIFY BJB fuses 3 (20A) and 16 (10A) are OK. If not OK, REFER to the OEM Wiring Diagrams to identify the possible causes of the circuit short. If OK, REPAIR the circuit.

B2 CHECK THE A/C (AIR CONDITIONING) CLUTCH RELAY
- Carry out the component test on the A/C clutch relay. Refer to Carry out the component test on the A/C clutch relay. Refer to Component Testing for schematic and connector information.
Did the relay pass the component test?

Yes GO to B3

No INSTALL a new A/C clutch relay.

B3 CHECK THE A/C (AIR CONDITIONING) CLUTCH RELAY CONTROL CIRCUIT FOR A SHORT TO VOLTAGE

Ignition OFF.

Disconnect A/C clutch relay.

Disconnect PCM, 6.7L Power Stroke Diesel C1232B , 6.2L V8 or 6.8L Triton-30V - V10 C175B .

Ignition ON.

Measure:

Positive Lead	Measurement / Action	Negative Lead
A/C clutch relay socket 2	Courtesy of FORD MOTOR COMPANY	Ground

Is any voltage present?

Yes	REPAIR the circuit.

GO to B4

B4 CHECK THE A/C (AIR CONDITIONING) CLUTCH RELAY CONTROL CIRCUIT FOR A SHORT TO GROUND

Ignition OFF.

Measure:

Positive Lead	Measurement / Action	Negative Lead
A/C clutch relay socket 2	Courtesy of FORD MOTOR COMPANY	Ground

Is the resistance greater than 10, 000 ohms?

Yes

GO to B5

No	REPAIR the circuit.

B5 CHECK THE A/C (AIR CONDITIONING) CLUTCH RELAY CONTROL CIRCUIT FOR AN OPEN

Measure:

6.7L Power Stroke Diesel

Positive Lead	Measurement / Action	Negative Lead
A/C clutch relay socket 2	Courtesy of FORD MOTOR COMPANY	C1232B-2

6.2L V8 or 6.8L Triton-30V - V10

Positive Lead	Measurement / Action	Negative Lead
A/C clutch relay socket 2	Courtesy of FORD MOTOR COMPANY	C175B-15

Is the resistance less than 3 ohms?

Yes

GO to B6

No	REPAIR the circuit.

B6 CHECK FOR CORRECT PCM (POWERTRAIN CONTROL MODULE) OPERATION

Ignition OFF.

Disconnect and inspect all PCM connectors.

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

Reconnect all PCM connectors. Make sure they seat and latch correctly.

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 PCM. Refer to: Powertrain Control Module (PCM) - 6.2L V8 . Refer to: Powertrain Control Module (PCM) - 6.8L Triton-30V - V10 . Refer to: Powertrain Control Module (PCM) - 6.7L Power Stroke Diesel .

No	The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector. ADDRESS the root cause of any connector or pin issues.