Generator: Diagnosis Mercury Cougar VIII

TROUBLE SHOOTING

Note. See TROUBLE SHOOTING article in GENERAL INFORMATION.

TEST A: CHARGE WARNING INDICATOR ON, FLICKERS OR IS INTERMITTENT WITH ENGINE RUNNING

1. Connect battery load tester according to manufacturer's instructions. Load battery at approximately one-half battery cold-cranking amperage rating for fifteen seconds. If battery voltage remains greater than 9.6 volts, go to next step. If battery voltage drops to less than 9.6 volts, charge battery and retest. If recharged battery tests okay, go to next step. If voltage still drops to less than 9.6 volts, replace battery and check system operation.
2. Perform «GENERATOR LOAD TEST»(ref-628-S26588840932000030800000) under ON-VEHICLE TESTING. If generator does not perform as specified, go to next step. If generator performs as specified, diagnose problem in instrument cluster. See appropriate INSTRUMENT PANELS article in ACCESSORIES & EQUIPMENT.
3. Start engine. Measure generator ground circuit voltage drop by connecting voltmeter positive probe to generator case, and voltmeter negative probe to battery negative terminal. If voltage is less than .5 volt, go to next step. If voltage is .5 volt or greater, clean and tighten generator mounting, and clean or repair ground cables. Recheck voltage drop. If voltage drop is still .5 volt or greater, replace negative battery cable and check system operation.
4. With engine still running, measure generator B+ circuit voltage drop by connecting voltmeter positive probe to generator B+ terminal (Orange/Yellow wire), and voltmeter negative probe to battery positive terminal. If voltage is less than .5 volt, go to next step. If voltage is .5 volt or greater, clean and tighten generator B+ connections, positive battery terminal connections and cable connections at starter motor. Recheck voltage drop. If voltage drop is still .5 volt or greater, replace positive battery cable and check system operation.
5. Measure voltage between generator terminal B+ (Orange/Yellow wire) and ground. If battery voltage is present, go to next step. If battery voltage is not present, inspect 175-amp fusible link. Replace as necessary. If fusible link is okay, repair circuit between battery, starter motor and generator. See «WIRING DIAGRAMS»(ref-628-S24581618222000030800000) .
6. Disconnect generator 3-pin connector. Measure voltage between generator 3-pin connector terminal No. 3 (Red wire) and ground. If voltage is 10 volts or less, inspect fuse in battery junction box and replace as necessary. If fuse is okay, repair circuit. See «WIRING DIAGRAMS»(ref-628-S24581618222000030800000) . On 2.5L, if voltage is greater than 10 volts, go to next step. On 2.0L, if voltage is greater than 10 volts, replace generator and check system operation. See «GENERATOR»(ref-628-S02574647172000030800000) under REMOVAL & INSTALLATION.
7. Disconnect generator 1-pin connector (Gray wire). Measure resistance of Gray wire between generator 3-pin connector terminal No. 2 and generator 1-pin connector terminal. If resistance is less than 5 ohms, replace generator. See «GENERATOR»(ref-628-S02574647172000030800000) under REMOVAL & INSTALLATION. If resistance is 5 ohms or greater, repair open in Gray wire. See «WIRING DIAGRAMS»(ref-628-S24581618222000030800000) .