Test A: Charging System Malfunction
- Start engine and let idle. Measure voltage between battery terminals. If battery voltage is 13-15 volts, problem is intermittent. Check for loose connections. If battery voltage is not 13-15 volts, go to next step.
- Turn ignition switch to OFF position. Inspect condition of accessory drive belt and tensioner. Replace drive belt as necessary and retest system operation. If belt is okay, go to next step.
- Inspect generator connectors and generator mounting for looseness or corrosion. If connections and mountings are not okay, repair as necessary and retest system operation. If connections and mounting are okay, go to next step.
- Inspect battery cables for clean and tight connections at battery. If connections are not okay, repair as necessary and retest system operation. If connections are okay, go to next step.
- Verify battery condition. Load test battery at one-half rated amperage for 15 seconds. If battery is okay, go to next step. If battery voltage drops to less than 9.6 volts, charge and retest system operation. If battery voltage still drops to less than 9.6 volts, replace battery and retest system operation.
- Turn ignition switch to OFF position. Disconnect generator 3-pin connector. Measure voltage between ground and generator connector terminal No. 3 (Orange/Light Blue wire). See Fig 1. If battery voltage is present, go to next step. If battery voltage is not present, repair open in Orange/Light Blue wire between generator and battery junction box. See WIRING DIAGRAMS .
- Reconnect generator 3-pin connector. Measure voltage between ground and Yellow/White wire terminal at generator terminal B+. If battery voltage is present, go to next step. If battery voltage is not present, repair open in Yellow/White wire between generator and fusible link "A". See WIRING DIAGRAMS .
- Check generator output. Perform GENERATOR LOAD TEST and GENERATOR NO-LOAD TEST
under ON-VEHICLE TESTING. If generator is okay, check system for intermittent failure. Perform TEST Z: INTERMITTENT under SYSTEM TESTS in appropriate SELF-DIAGNOSTICS - EEC-V - GASOLINE & NGV article in ENGINE PERFORMANCE. If generator is not okay, continue diagnosis of PCM controlled charging system. See TEST HY: GENERATOR/REGULATOR SYSTEM under SYSTEM TESTS in appropriate SELF-DIAGNOSTICS - EEC-V - GASOLINE & NGV article in ENGINE PERFORMANCE.
Courtesy of FORD MOTOR CO.