Ford F-150 1999 - Pinpoint Test C: Compressor Clutch Coil and Circuit Checks; Clutch Coil Voltage, Ground, and Circuit 321 Checks

A/C Compressor Clutch Field Coil C106
Measure the voltage between the A/C compressor clutch field coil C106, circuit 321 (GY/WH) and ground.
 Is the voltage reading greater than 10 volts?
Yes
GO to C14.
No
GO to C15.
C14 CHECK FOR GROUND AT THE A/C COMPRESSOR CLUTCH FIELD COIL
Measure the resistance between the A/C compressor clutch field coil C106, circuit 57 (BK) and ground.
 Is the resistance less than 5 ohms?
Yes
GO to C19.
No
REPAIR circuit 57 (BK). TEST the system for normal operation.
C15 CHECK CIRCUIT 321 (GY/WH)
A/C Clutch Relay
Measure the resistance between the A/C clutch relay socket pin 5, circuit 321 (GY/WH) and the A/C compressor
clutch field coil C106, circuit 321 (GY/WH).
 Is the resistance less than 5 ohms?
Yes
GO to C16.
No
REPAIR Circuit 321(GY/WH). TEST the system for normal operation.
Page 16 of 301999 F-150/250 Workshop Manual
8/16/2010http://www.fordtechservice.dealerconnection.com/pubs/con...