On-Vehicle Inspection: Preparation
- Turn the ignition switch to "OFF".
- Disconnect the output wire from the alternator "B" terminal. Connect the (+) lead wire of ammeter to the "B" terminal of alternator and the (-) lead wire of ammeter to the output wire. Connect the (+) lead wire of voltmeter to the "B" terminal of alternator and the (-) lead wire of voltmeter to the (+) terminal of battery.
- Prior to the test, check the following items and correct as necessary.
Check the battery installed in the vehicle to ensure that it is in good condition. The battery checking method is described in the "Battery" service information.
The battery that is used to test the output current should be one that has been partially discharged. With a fully charged battery, the test may not be conducted correctly due to an insufficient load.
Check the tension of the alternator drive belt. The belt tension check method is described in the "Inspect drive belt" service information.
- Turn off the ignition switch.
- Disconnect the battery ground cable.
- Disconnect the alternator output wire from the alternator "B" terminal.
- Connect a DC ammeter (0 to 150A) in series between the "B" terminal and the disconnected output wire. Be sure to connect the (-) lead wire of the ammeter to the disconnected output wire.NOTE: Tighten each connection securely, as a heavy current will flow. Do not rely on clips.
- Connect a voltmeter (0 to 20V) between the "B" terminal and ground. Connect the (+) lead wire to the alternator "B" terminal and (-) lead wire to a good ground.
- Attach an engine tachometer and connect the battery ground cable.
- Leave the engine hood open.
- Prior to the test, check the following items and correct if necessary.
Check that the battery installed on the vehicle is fully charged. The battery checking method is described in the "Battery" service information.
Check the alternator drive belt tension. The belt tension check method is described in the "Inspect drive belt" service information.
- Turn ignition switch to "OFF".
- Disconnect the battery ground cable.
- Connect a digital voltmeter between the "B" terminal of the alternator and ground. Connect the (+) lead of the voltmeter to the "B" terminal of the alternator. Connect the (-) lead to good ground or the battery (-) terminal.
- Disconnect the alternator output wire from the alternator "B" terminal.
- Connect a DC ammeter (0 to 150A) in series between the "B" terminal and the disconnected output wire.
Connect the (-) lead wire of the ammeter to the disconnected output wire.
- Attach the engine tachometer and connect the battery ground cable.