Generator/Regulator Test
CAUTION:
When performing full field test on generator, charging voltage will increase quickly. DO NOT allow voltage to increase to more than 18 volts, or electrical system will be damaged.
- Ensure battery is fully charged and in good condition. Connect Generator Tester (Sun VAT-40). Set tester selector switch to position No. 1 (starting). Place transmission in Park (A/T) or Neutral (M/T). Ensure all accessories are off. Start engine. Operate engine at 3000 RPM until cooling fan comes on, then return to idle. Increase engine speed and hold at 2000 RPM. Check voltage reading on tester. If voltage reading is more than 15.1 volts, replace voltage regulator. If voltage reading is 15.1 volts or less, go to next step.
- Let engine idle. Ensure all accessories are off. Turn tester selector switch to position No. 2 (charging). Remove tester's inductive pick-up and zero ammeter. Place inductive pick-up on battery ground cable with arrow pointing toward battery negative terminal. Increase engine speed and hold at 2000 RPM. If voltage reading is less than 13.5 volts, replace or repair generator. If voltage reading is 13.5 volts or more, go to next step.
- Using generator tester, apply load until battery voltage drops to 12.0-13.5 volts. Compare amperage reading on tester against expected minimum value. See GENERATOR TEST OUTPUT SPECIFICATIONS table under GENERATOR SPECIFICATIONS. If amperage reading is as specified, charging system is okay. If amperage reading is not as specified, go to next step.
- Maintain engine speed at 2000 RPM. Full field generator using generator tester full-field test probe. See Fig 1 . Switch tester field selector to "A" (ground) position momentarily. Check amperage reading and compare with expected minimum value. See GENERATOR TEST OUTPUT SPECIFICATIONS table under GENERATOR SPECIFICATIONS. If generator output is as specified, replace voltage regulator. If generator output is not as specified, replace or repair generator.