SYS.OK|MANUAL.DB● LIVE
HOMESERVICE MANUALSFORD1994ASPIRE SE, AUTOMATICREPAIR AND DIAGNOSIS (SINGLE PAGE)HEATING, VENTILATION & A/C (HVAC)HVAC CONTROL SYSTEMSA/C-HEATER SYSTEM - MANUALTROUBLE SHOOTINGA/C COMPRESSOR CLUTCH DOES NOT ENGAGE
1994 Ford Aspire SE, Automatic

A/C Compressor Clutch Does Not Engage

1994 Ford Aspire SE, AutomaticSECTION A/C Compressor Clutch Does Not Engage
  1. Refrigerant Check  Check A/C system performance. See A/C SYSTEM PERFORMANCE under TESTING. If A/C system performance is not okay, service A/C system. If A/C system performance is okay, go to next step.
  2. Fuse Check  Turn ignition off. Check wiper fuse located in passenger compartment fuse/junction panel. Check cooling fan fuse in main fuse/junction panel. If fuses are okay, go to step 5). If either fuse is blown, go to next step.
  3. With ignition off, replace blown fuse(s). Turn ignition on. If fuse does not blow, go to step 5). If fuse blows, go to next step.
  4. Short Circuit Check  Turn ignition off. Remove blown fuse(s). Disconnect A/C compressor clutch control relay connector. Measure resistance of Blue wire between ground and wiper fuse holder. Measure resistance of White/Black wire between ground and cooling fan fuse holder. If resistance is less than 5 ohms, repair short to ground in wire(s). If resistance is more than 5 ohms, replace appropriate fuse and go to next step.
  5. A/C Compressor Clutch Check  Turn ignition off. Disconnect A/C compressor clutch connector from thermo protection switch. Apply 12 volts to Black wire at connector leading to A/C clutch. The A/C clutch hub should pull in when 12 volts is applied, and release when 12 volts is removed. If A/C clutch hub does not operate as specified, replace A/C compressor clutch. If A/C clutch hub operates as specified, go to next step.
  6. Thermo Protection Switch Check  Turn ignition off. Disconnect both thermo protection switch connectors. Measure thermo protection switch resistance. If resistance is more than 5 ohms, replace thermo protection switch. If resistance is less than 5 ohms, go to next step.
  7. A/C Compressor Clutch Control Relay Check  Turn ignition off. Remove A/C compressor clutch control relay. Apply 12 volts to Blue wire and White/Black wire terminals of relay. Measure voltage on Green/White wire terminal of relay while grounding and opening Blue/Orange wire terminal of relay. Voltage should be more than 10 volts with relay grounded, and less than one volt with relay ungrounded (open). If relay does not operate as specified, replace A/C compressor clutch control relay. If relay operates as specified, go to next step.
  8. Power Supply Check  Turn ignition off. Remove A/C compressor clutch control relay. Turn ignition on. Measure voltage on Blue wire and White/Black wire at A/C compressor clutch control relay connector. If voltage readings are less than 10 volts, repair open wire(s). If voltage readings are more than 10 volts, go to next step.
  9. A/C Switch Check  Turn ignition and A/C switches off. Disconnect A/C switch connector. Measure A/C switch resistance between Blue/Yellow wire terminal and Green/Black wire terminal with switch off and then on. Resistance should be less than 5 ohms with switch on, and more than 10,000 ohms with switch off. If resistance values are not as specified, replace A/C switch. If resistance values are as specified, go to next step.
  10. A/C Switch Ground Circuit Check  Turn ignition off. Disconnect A/C switch connector. Place blower motor switch in low speed position. Measure resistance of Blue/Yellow wire between A/C switch connector and ground. If resistance is more than 5 ohms, repair open Blue/Yellow wire. If resistance is less than 5 ohms, go to next step.
  11. Wiring Harness Check  Turn ignition off. Disconnect A/C switch connector. Disconnect integrated control thermistor probe connectors. Measure resistance of Green/Black wire between A/C switch and thermistor probe connectors. If resistance is more than 5 ohms, repair open Green/Black wire. If resistance is less than 5 ohms, go to next step.
  12. Integrated Control Thermistor Probe Check  Turn ignition off. Disconnect integrated control thermistor probe connectors. Measure thermistor probe resistance. If resistance is more than 5 ohms, replace integrated control thermistor probe. If resistance is less than 5 ohms, go to next step.
  13. Wiring Harness Check  Turn ignition off. Disconnect integrated control thermistor probe connectors. Disconnect A/C pressure cut-off switch connector. Measure resistance of Green/Red wire between thermistor probe and A/C pressure cut-off switch connector terminals. If resistance is more than 5 ohms, repair open Green/Red wire. If resistance is less than 5 ohms, go to next step.
  14. A/C Pressure Cut-Off Switch Check  Turn ignition off. Disconnect A/C pressure cut-off switch connector. Measure A/C pressure cut-off switch resistance. If resistance is more than 5 ohms, replace A/C pressure cut-off switch. If resistance is less than 5 ohms, go to next step.
  15. Wiring Harness Check  Turn ignition off. Remove A/C compressor clutch control relay. Disconnect A/C compressor clutch connector. Measure resistance of Green/White wire between A/C compressor clutch control relay connector and A/C compressor clutch connector, and then between relay connector and ground. Resistance should be less than 5 ohms between A/C compressor clutch control relay and A/C compressor clutch, and more than 10,000 ohms between relay and ground. If resistance is not as specified, repair open Green/White wire. If resistance is as specified, check PCM A/C compressor control relay circuit. See TESTS W/CODES article in the ENGINE PERFORMANCE section.
RENDER: 1.0x

NO RELATED

Recommended Tools & Savings

Use the Manual With the Right Hardware

Pair factory procedures with proven DIY tools so the instructions are easier to execute.

Affiliate disclosure: We may earn a commission at no extra cost to you.

Shop Manual-Ready ToolsFree Quote CheckQuote Shield Pro

When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • • You smell fuel, burning insulation, or see smoke.
  • • Brakes feel soft, pull hard to one side, or make grinding noises.
  • • The engine overheats, stalls repeatedly, or misfires under load.
  • • You are missing required tools, torque specs, or safe lifting equipment.
  • • You are not confident in the next step or safety outcome.