Charging system tests:
No load idle output test-
Conect the red lead of your DMM to the B+ on the alternator, conect the black lead to the battery negative.Now conected an amp clamp to the wire/s coming from the B+ on the alternator. Start the engine, with all electrical acessorys turned off. Charging voltage should be aroung 13 more or less. To see how your regulator reacts, get somone to quickly rev the engine, while still watching the DMM and ammeter. The voltage output should jump quickly and leval off at 14.6v more of less.
Alternator Max output test:
For this you will need the DMM and Amp clamp as well as a Battery load tester.
Hook up the amp clamp and the DMM in the same way as the no load test, but this time, conect the batt' load tester to the battery. Get somone to hop in the truck, start it, and rev it up to about 2000rpm. Get them to hold it there during the test. Useing the load tester, load the system down to 13.5 Volts, and read Again, record the reading from the DMM and the output amps. dont load it down for too long, or you will let the smoke out of the load tester, thats not good. So, now your done the Alternator output tests. Voltage drops are done useing the same idea, high idle, load the system down, and check the Vd on both the positive and negative sides of the circuit. Go from center of the batt post to the center of the conector, this way the resistance in the conections them selves will be measured as well. If you find that when you do the high idle test, and the amperage does not increase much, then you need to look at the regulator, if you find that nothing happens at all, you should find out of you are getting voltage to the I termanal on the alternator. You should get 12 volts at that wire with the key on, engine off.