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Home >> Mercury Truck >> 1998 >> Villager V6-181 3.0L SOHC VIN 1 EFI >> Repair and Diagnosis >> Starting and Charging >> Charging System >> Testing and Inspection >> Component Tests and General Diagnostics >> Generator Testing >> Generator On-Vehicle Tests

Generator On-Vehicle Tests

LOAD TEST







1. Connect the leads of Rotunda Alternator, Regulator, Battery and Starter Tester (ARBST) 010-00725 or equivalent to the vehicle, observing proper polarity.

NOTE: Battery and cable clamps must be clean and tight to ensure accurate meter indications. Before performing any generator tests, inspect the drive belt for looseness, damage and wear. If necessary, adjust the drive belt for proper tension.

2. Turn all electrical accessories off.
3. Turn ARBST unit on.
4. Initiate test by pushing the charging system test button on ARBST unit.
5. Start the engine and run at approximately 2000 rpm. Test will be performed automatically.
6. Return the engine to idle; second part of test will be performed automatically.
7. The ARBST unit will give peak amperage reading, peak voltage reading and diode pattern condition at conclusion of test.
8. If the peak amperage output is within 10 percent of the generator's rated output, the Generator (GEN) is functioning properly. The Generator Specifications shows the appropriate amperage output. If the amperage output is below specification, proceed with the next test.

GENERATOR SPECIFICATIONS
Nominal Rating - 12 V-110 A
Hot Output Current - More than 33 A/1300 RPM
- More than 85 A/2500 RPM

NO-LOAD TEST







1. With the key in the ON position and the engine not running, verify that the voltage at the generator wiring connector terminals are as follows:
- B-terminal = Battery Voltage
- L-terminal = 1.5-2.0 volts
- S-terminal = Battery Voltage

CAUTION: Do not ground the B-terminal.

2. Start the engine.







3. With the engine running and at normal curb idle, verify that the voltage at the generator wiring connector terminals is as follows:
- B-terminal = 14.1-14.7 volts
- L-terminal = 13.0-14.0 volts
- S-terminal = 14.1-14.7 volts

4. If the voltages are as specified, check the wiring harness between the battery and the B-terminal. If the voltages are below specification, check the wiring harness. If the wiring harness is in good condition, repair or replace the generator.

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