Ford A/C Compressor Clutch Diode Test A18-A19 - Circuits 31-CA6/31-CA7 Diagnosis

This document is a screenshot of a Ford dealer technical service website (fordtechservice.dealerconnection.com) showing a portion of an A/C system pinpoint diagnostic test procedure. It covers steps in diagnosing the A/C compressor clutch circuit. Step 2 of one test directs measuring resistance between A/C compressor clutch diode connector C972, pin 1, circuit 31-CA7 (BK, black wire) and ground; less than 5 ohms passes to step A18, otherwise circuit 31-CA7 must be repaired. Step A18, 'CHECK THE A/C COMPRESSOR CLUTCH DIODE,' instructs checking continuity between the diode terminals in both directions, continuity in one direction only indicates a good diode (go to A19); otherwise install a new A/C compressor clutch diode. Step A19, 'CHECK CIRCUIT 31-CA6 (BK) FOR OPEN,' begins with measuring resistance between A/C clutch solenoid connector C952, pin 2, circuit 31-CA6 (BK) and ground (the rest of this step is cut off). Illustrations GL1653A and GL1654A show ohmmeter hookups for the measurements. A reader learns the exact connector pins, wire circuit numbers/colors, pass/fail criteria, and repair actions for testing the A/C compressor clutch diode and related ground circuits.