ALTERNATOR OUTPUT LINE VOLTAGE DROP TEST

This test determines whether the wiring from the alternator "B" terminal to the battery (+) terminal (including the fusible line) is in a good condition or not.
1.Always be sure to check the following before the test.

Alternator installation
Drive belt tension
(Refer to , GROUP 11A - On-Vehicle Service.)
Fusible link
Abnormal noise from the alternator while the engine is running

2.Turn the ignition switch to the "LOCK" (OFF) position.
3.Disconnect the negative battery cable.
4.Connect a clamp-type DC test ammeter with a range of 0 - 150 A to the alternator "B" terminal output wire.

note

The way of disconnecting the alternator output wire and of connecting the ammeter is possibly not found the problem that the output current is dropping due to the insufficient connection between terminal "B" and the output wire.

5.Connect a digital-type voltmeter between the alternator "B" terminal and the battery (+) terminal. [Connect the (+) lead of the voltmeter to the "B" terminal and the connect the (-) lead of the voltmeter to the battery (+) cable].
6.Reconnect the negative battery cable.
7.Connect the M.U.T.-III (to show the engine speed).
8.Leave the hood open.
9.Start the engine.
10.With the engine running at 2,500 r/min, turn the headlamps and other lamps on and off to adjust the alternator load so that the value displayed on the ammeter is slightly above 30 A.
Adjust the engine speed by gradually decreasing it until the value displayed on the ammeter is 30 A. Take a reading of the value displayed on the voltmeter at this time.
Limit: maximum 0.3 V

note

When the alternator output is high and the value displayed on the ammeter does not decrease until 30 A, set the value to 40 A. Read the value displayed on the voltmeter at this time. When the value range is 40 A, the limit is maximum 0.4 V.

11.If the value displayed on the voltmeter is above the limit value, there is probably a malfunction in the alternator output wire, so check the wiring between the alternator "B" terminal and the battery (+) terminal (including fusible link).
If a terminal is not sufficiently tight or if the harness has become discolored due to overheating, repair and then test again.
12.After the test, run the engine at idle.
13.Turn off all lamps.
14.Turn the ignition switch to the "LOCK" (OFF) position.
15.Remove the M.U.T.-III.
16.Disconnect the negative battery cable.
17.Disconnect the ammeter and voltmeter.
18.Connect the negative battery cable.