Alternator or battery problem?
I went to start my 90 gmc up and the battery was dead.There was not anything left on and it has never happened before.I jump started it and drove it around and while it was running the guage said 12-14 volts.I turned off the truck and tried to restart it and nothing.I did that twice.Is my battery just dead and won’t live again or is it the alternator not charging?Any tips on how to check this stuff?Thanks Response: You could test further before making the decision, but the battery is most likely dead.