96 silverado problems help

latley all of the power in my truck has been very inconsistant. i cant figure out why it happens. i have check all my fuses, i have checked my battery, and it will fire up once in a while and only for a while. any ideas?

try putting a multimeter on a/c volts and take a reading from the power lead to the alternator and ground while it's running. if you get any reading in a/c , one or more of the diodes are not operating. of course any number of things may cause your condition, but it might be something people miss.

as swingline said it sounds undoubtedly to be an alternator problem. most auto parts stores offer free alternator checks heres a very short list of those that do (Advance auto parts, Checker) told ya it was short. anyways if youve got a diode problem and your alternator is pumping out AC current that can damage quite a few vital components. as i work at valvoline, We offer free systems checks with our Interstate ED-18 its basically an electrical diagnostics tester it tests cranking output, alternator output, and entire charging system problems. i would personally recommend that if you are to replace your alternator you get an autolite with their lifetime warranty ive used my warranty twice, once was my fault :(