Ford F150 Pickup. Instruction - part 1681

Fig. 9: Locating A/C Cycling Switch 
Courtesy of FORD MOTOR CO. 

The A/C cycling switch is mounted on a Schrader valve-type fitting on the top of the suction accumulator. 

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A valve depressor, located inside the threaded end of the A/C cycling switch, presses in on the Schrader 
valve stem.  

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This allows the suction pressure inside the suction accumulator/drier to control the operation of the A/C 
cycling switch.  

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The electrical switch contacts open when the suction pressure drops, the contacts close when the suction 
pressure rises. For specifications regarding operating pressure(s), refer to CLIMATE CONTROL 
SYSTEM .  

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When the A/C cycling switch contacts close, the A/C clutch field coil is energized.  

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When the A/C cycling switch contacts open, the A/C clutch field coil is de-energized and compressor 
operation stops.  

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The A/C cycling switch will control the A/C evaporator core pressure at a point where the plate/fin 
surface temperature will be maintained slightly above freezing.  

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This prevents icing of the A/C evaporator core and blockage of airflow.  

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It is not necessary to discharge the refrigerant system to remove the A/C cycling switch.  

A/C Pressure Cut-Off Switch 

 

2003 Ford Pickup F150 

2003 HVAC Air Conditioning - F150 Pickup

  

Fig. 10: Identifying A/C Pressure Cut-Off Switch 
Courtesy of FORD MOTOR CO. 

The A/C pressure cutoff switch is used to interrupt the A/C compressor operation in the event of high system 
discharge pressures. 

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The A/C pressure cutoff switch is mounted on a Schrader valve-type fitting on the high pressure side of 
the A/C manifold and tube.  

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A valve depressor, located inside the threaded end of the A/C pressure cutoff switch, presses on the 
Schrader valve stem.  

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This allows the A/C pressure cutoff switch to monitor the compressor discharge pressure.  

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When the compressor discharge pressure rises the switch contacts open, disengaging the A/C compressor. 

 

2003 Ford Pickup F150 

2003 HVAC Air Conditioning - F150 Pickup

  

When the pressure drops the contacts close to allow operation of the A/C compressor. For specifications 
regarding operating pressure(s), refer to CLIMATE CONTROL SYSTEM .  

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It is not necessary to discharge the refrigerant system to remove the A/C pressure cutoff switch.  

Spring Lock Coupling 

 

2003 Ford Pickup F150 

2003 HVAC Air Conditioning - F150 Pickup

  

Fig. 11: Identifying Spring Lock Coupling Components
Courtesy of FORD MOTOR CO. 

The spring lock coupling is a refrigerant line coupling held together by a garter spring inside a circular cage. 

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When the coupling is connected together, the flared end of the female fitting slips behind the garter spring 
inside the cage of the male fitting.  

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The garter spring and cage then prevent the flared end of the female fitting from pulling out of the cage.  

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Three O-ring seals are used to seal between the two halves of the A/C condenser core couplings, all other 
couplings have two O-ring seals.  

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Use only the O-ring seals listed in the Ford Master Parts Catalog for the spring lock coupling.  

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A plastic indicator ring is used on the spring lock couplings of the A/C evaporator core to indicate, during 
vehicle assembly, that the coupling is connected. Once the coupling is connected, the indicator ring is no 
longer necessary but will remain captive by the coupling near the cage opening.  

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The indicator ring may also be used during repair operations to indicate connection of the coupling.  

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An A/C tube lock coupling clip (19E746) may be used to secure the coupling but is not required.  

Service Gauge Port Valves 

The high pressure service gauge port valve is located on the A/C manifold and tube. 

The low pressure service gauge port valve is located on the suction accumulator. 

DIAGNOSIS AND TESTING 

AIR CONDITIONING 

Refer to CLIMATE CONTROL SYSTEM .

 

2003 Ford Pickup F150 

2003 HVAC Air Conditioning - F150 Pickup