1990 GMC Jimmy Q&A
1990 GMC Jimmy Question: Have to jump to start. New battery & alternator is charging at 13.5 volts.
Something is draining the battery overnight. Close all doors and make sure there is no interior lights left on. Check glove box light. Check under hood light. If all are off then take it to a shop that has the equipment and diagrams to diagnose a draw on the battery could be almost anything. - Justin Case Auto