Reader Question: I have 1998 Ford Ranger Pickup Truck 2.5 Liter 4 cylinders, 2WD. Each time vehicle is not driven for a while (overnight), battery is dead.
(1) Alternator is good (charging at 14.5)
(2) Battery is good
(3) Alternator fuse is good
After getting jumped, vehicle runs fine, but battery dash light is on.
Nothing seems to be on and draining when vehicle is off.
If the battery passes a load test AND the alternator is recharging the battery then the only thing left is a voltage drain in the system somewhere. You are going to have to check for a drain and start unplugging the things until you find it.
Usually the battery light is on the dash because the battery has a bad internal cell and is not holding a charge or there is a problem with not receiving electrical supply from the alternator…bad alternator, bad voltage regulator or bad connection between the alternator and the battery like a ground problem or a battery cable problem.