Take your meter and with the truck off, measure the voltage at the bat output lug on the back of the alternator. If you do not get 12v there, then the fusible link is burnt out. This is usually caused by changing/messing around with the alternator wiring without disconnecting the battery. Happens all the time. Then the alternator is just out there by itself, not charging the battery because the fusible link is blown.
If you get 12v on the back of the alternator, some other things to check;
Put your meter lead on ground and put the other lead on the "I" terminal of the regulator(red/green wire) While holding the meter, get someone to turn the key to run but don't start the truck. When they do that, you should get voltage on the "I" terminal, this comes from the lightbulb in the dash and brings the system online and ready to charge. If you don't get anything, you still have dash problems.
The "A" terminal on the reg should have battery voltage at all times. This terminal is the monitor for the voltage regulator, the regulator uses this info to tell the alternator how much to put out.
The "S" terminal goes directly to the alternator.
The "F" terminal is the output of the regulator and more or less voltage on this wire will vary the output of the alternator. When you jumped the A and the F, you put full voltage on the F and the alternator should have gone wide open. It may have, but you didn't see it if the fusible link is burnt out.