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Home >> Ford >> 2019 >> Expedition MAX SSV, 4WD >> Repair and Diagnosis (Single Page) >> Heating, Ventilation & A/C (HVAC) >> HVAC Control Systems >> Climate Control System - General Information (2 Of 2) >> Diagnosis And Testing >> Climate Control System - Vehicles With: Electronic Manual Temperature Control (EMTC) >> Pinpoint Test(s) >> Pinpoint Test B : P0645 >> Notes
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Pinpoint Test B : P0645: Notes

Refer to Manual Climate Control System for schematic and connector information.

Normal Operation and Fault Conditions 

Voltage is provided to the A/C clutch relay with the key on. When A/C is requested and A/C line pressures allow, a ground is provided to the A/C clutch relay coil from the PCM, energizing the A/C clutch relay. The A/C clutch relay is a non serviceable part of the printed circuit board on the  BJB.

DTC Fault Trigger Conditions 

DTC Description Fault Trigger Conditions
P0645 A/C Clutch Relay Control Circuit This DTC sets when the PCM grounds the relay circuit and more voltage than expected is detected on the relay circuit. This DTC also sets when the relay circuit is off and no voltage is detected on the relay circuit. The PCM expects to detect voltage coming through the relay coil to the relay circuit when it is not grounding it.

Possible Sources 

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