You can check to see if a GENERATOR type charging system is working by disconnecting the battery cable. If the vehicle still keeps running chances are good things are working. If the vehicle engine dies whenyou remove the battery cable from the battery either the charging system needs some attention or......you ran out of gasoline!
DO NOT remove the battery cable from the battery to check an ALTERNATOR type of charging system. You will likely be shopping for a new alternator. The stray arcs and sparks created when you remove the battery cable will burn out the solid state compoents inside the alternator, like the diodes and the regulator.
Instead just place a flat screwdriver on the smooth bearing surface on the back of the alternator, while the engine is running. If the alternator is charging... this surface will be magnetized. If you still have doubts turn on headlights, heater blower motor etc to increase the electrical load. Then there will be little doubt.
A snap-on red handled screwdriver number 7 works best for this test, but in a pinch a Craftsman clear handled number 4 will get you by. If you have neither of those just use the blade of your brother-in-law's pocket knife. If you have none of these, carefully and quietly sneak into the house, go to the kitchen, get into the silverware drawer, and grab a silverware knife.
If you get caught, no one on this board knows you... or has ever seen your truck before.
