Generator On-Vehicle Tests - Load Test

Switch the tester to the ammeter function.
Connect the positive and negative leads of the battery tester to the corresponding battery terminals.
Connect the current probe to the generator B+ output terminal, circuit 36 (YE/WH).
With the engine running at 2,000 rpm, adjust the tester load bank to determine the output of the generator. Generator output should be at least 87 amps.

Fig 1: Generator Output Graph
Courtesy of FORD MOTOR CO.
With the engine running, turn the A/C on, the blower motor on high speed and the headlamps on high beam.
Increase the engine speed to approximately 2,000 rpm. The voltage should increase a minimum of 0.5 volt above the base voltage.
- If the voltage does not increase as specified, carry out the GENERATOR ON-VEHICLE TESTS - NO LOAD TEST , in this article.
- If the voltage increases as specified, the charging system is operating normally.