Compressor Clutch: Testing and Inspection

A/C Compressor Clutch Check

1. Check the armature plate for discoloration, peeling, or other damage. If there is damage, replace the clutch set. Service and Repair

2. Check the rotor pulley bearing play and drag by rotating the rotor pulley by hand. Also check for grease leakage from the bearing. Replace the clutch set with a new one if it is noisy, has excessive play/drag, or has bearing grease contamination on the clutch faces. Service and Repair
NOTE: The rotor pulley and the armature plate were mated at the factory by a bumishing operation. Always replace the pulley and the plate as a set. Replacing only one part of the clutch set will cause clutch slippage.






3. Measure the clearance between the rotor pulley (A) and the armature plate (B) all the way around. If the clearance is not within specified limits, remove the armature plate Service and Repair and add or remove shims as needed to increase or decrease clearance.





NOTE: The shims are available in four thicknesses: 0.1 mm, 0.2 mm, 0.4 mm, and 0.5 mm.






4. Measure the resistance between the A/C compressor clutch connector terminal No. 2 and the compressor housing. If resistance is not within specifications, replace the field coil. Service and Repair










5. Remove the bolt and the holders (A), then disconnect 1P connectors (B). Check the thermal protector for continuity. If there is no continuity, replace the thermal protector. Service and Repair
NOTE: The thermal protector will have no continuity above about 252 to 262 °F (122 to 128 °C). When the temperature drops below about 241 to 219 °F (116 to 104 °C), the thermal protector will have continuity.






6. Check the thermal fuse for continuity between the A/C compressor clutch connector terminal No. 1 and the 1P connector (A). If there is no continuity, replace the field coil. Service and Repair

7. Remove the armature palate, Service and Repair and inspect the armature palate and pulley friction surfaces for wear. If there is excessive wear, roughness, or scoring, replace the clutch set.

8. Inspect the friction surfaces and the compressor shaft hub for excess oil. If excess oil is present, and it is not from the engine or power steering system, then the compressor shaft seal is leaking. Replace the compressor. Service and Repair