Just to add another thing my alternator is working somewhat as I can leave the car running for an extended period of time and it won't die
check your battery voltage without the truck running, then do a no load test. check the battery voltage while running, it should be between 13-15 volts. total increase should be anywhere from .5v to 2v. if it didnt increase the alternator or wiring is bad. did you buy a reman'd alternator? EDIT: just saw your recent post if it passes this test do a load test on it bring engine to 2k RPMs and turn on lights, blower, wipers and anything else, battery voltage should increase atleast .5 from the no load test. if it didnt increase .5v or more take it back and replace it.
ok....i see no suggestions for a voltage regulator...i used to have the same problem with an old 78 truck i had...new voltage regulator and problem solved
the test could point out a faulty voltage reg if its not charging. the voltage regulators are usually inside the alts on the newer cars though so youd just replace te whole thing
