QuestionHi Ted,
I have a basic 1987 Toyota truck with a 22R engine and alternator with internal voltage regulator. My alternator light came on yesterday, so I'm trying to diagnose problem. The belt is fine. I need to test the alternator in place. I have a Haynes manual. For 2 separate testing procedures, I need to identify terminals "B" and "F." The manual has some lousy diagrams, and I can't figure out how to do this. Though the manual doesn't show or explain it, apparently terminal B is one of the terminals connected via the 3 prong plug because the B terminal is labeled on the alternator. I'm wondering if I connect my multi-meter so that it is between terminal B and its plug prong, should I somehow connect the other 2 plug prongs to their corresponding terminals on the alternator? If so, am I expected to just rig this as best I can, or am I expected to find/buy some individual connecting plugs/wires?
Regarding terminal F, the manual says that it needs to be grounded for the test. Although it has a diagram supposedly identifying where it is, the diagram doesn't look like the back of my alternator, and I can't find it. So, my question is, where is terminal F? Also, how should I ground it so that I can test the alternator while the engine is running?
Thanks,
Scott
AnswerI think you are overcomplicating matters a little,since the regulator is integral to the alternator there is no need to ground the F (field) terminal, if the regulator is malfunctioning or there is a diode problem the alternator simply gets replaced, we do not repair alternators, it's just not practical.
The point I'm making is that the tests you want to do are irrelevant, check the alternator output with a volt/ammeter if possible, ideally you should test it with a tester that can put an electrical load on it, a quick way to test it is to connect a voltmeter across the battery, with the engine running at idle there should be at least 13.8 volts, if not, replace the alternator with a decent remanufactured one.
