[johnjzjz]

the alt is a good bet - inside it has a diode treo when it goes bad - and even tho it charges correctly when not running the magnetic part is energized so it drains the battery -- the older cars had clocks that drained the battery and than it was the radio that was the problem today ?? but as was said ^ take off the ground and connect a test light between the battery and the cable and the light should be out if not start unplugging - note when you open the door the light will be on or if the car has a hood light that will also turn on test light -- easy stuff just take your time -- jz