COIL RESISTANCE TEST
- Disconnect and isolate the negative battery cable.
- Disconnect the wire harness connector from the A/C clutch coil connector.
- Use an ohm meter and Back Probe Tool (special tool #6801, Terminal Probe) and measure the resistance of the A/C clutch coil at the coil connector terminals.
- See A/C Clutch Coil Specifications table for acceptable A/C clutch coil resistance. Specifications apply for a work area temperature of 21° C (70° F). If the A/C clutch coil reading is below specifications, the coil is shorted and must be replaced. If the A/C clutch coil reading is above specifications, the coil is open and must be replaced.
COIL CURRENT DRAW TEST
- Verify the battery state of charge.
- Connect an ammeter (0 to 10 ampere scale selected) in series with the A/C clutch coil feed terminal using Back Probe Tool (special tool #6801, Terminal Probe). Connect a voltmeter (0 to 20 volt scale selected) to measure voltage across the battery and the A/C clutch coil.
- With the A/C-heater control in the A/C mode and the blower motor at low speed, start the engine and allow it to run at a normal idle speed.
- The A/C clutch should engage immediately and the clutch coil supply voltage should be within two volts of the battery voltage. If the clutch coil supply voltage is OK, go to 5 . If the coil supply voltage is not within two volts of battery voltage, test the clutch coil feed circuit for excessive voltage drop and repair as necessary.
- See A/C Clutch Coil Specifications table for acceptable A/C clutch coil current draw. Specifications apply for a work area temperature of 21° C (70° F). If voltage is more than 12.5 volts, add electrical loads by turning on electrical accessories until voltage reads below 12.5 volts. If the A/C clutch coil current reading is zero, the coil is open and must be replaced. If the A/C clutch coil current reading is above specifications, the coil is shorted and must be replaced.
| Coil Resistance | Coil Current Draw |
|---|---|
| 3.6 ± 0.2 ohms | 3.2 - 3.3 amps @ 12V ± 0.5V @ 21° C (70° F) |
A/C CLUTCH COIL SPECIFICATIONS
DIAGNOSIS AND TESTING - BLOWER MOTOR RESISTOR
| WARNING | Disable the airbag system before attempting any steering wheel, steering column, or instrument panel component diagnosis or service. Disconnect and isolate the negative battery (ground) cable, then wait two minutes for the airbag system capacitor to discharge before performing further diagnosis or service. This is the only sure way to disable the airbag system. Failure to take the proper precautions may result in accidental airbag deployment and possible serious or fatal injury. |
Note. See Wiring Information for circuit descriptions and diagrams. Wiring Information includes wiring diagrams, proper wire and connector repair procedures, further details on wire harness routing and retention, as well as pin-out and location views for the various wire harness connectors, splices and grounds.
- Disconnect and isolate the negative battery cable.
- Disconnect the wire harness connector from the blower motor resistor. Refer to «RESISTOR, BLOWER MOTOR, REMOVAL»(ref-476508-S36391285822012060400000) .
- Using an ohmmeter, check for continuity between all of the blower motor resistor terminals. In each case there should be continuity. If OK, repair the wire harness circuits between the blower motor speed control and the blower motor resistor or blower motor as required. If not OK, replace the inoperative blower motor resistor.