Charging system

You have a 12 volt electrical draw draining the battery. A short in the 12 system. To locate the circuit that the problem is related to you must do a draw test. this is done with a 12 light tester. First remove the fuses that would normally run when the vehicle is turned off such as the dome light, litter fuse as well as clock or radio fuse.Remove the fugitive cable from the battery negative battery post secure the tester clip to the negative post of the battery and touch the probe end to the removed negative cable. The tester is now inline with the power draw and the light should not be lit. If it is pull one fuse at a time to see if the light goes out. If it does that is the circuit where the draw is coming from. Check all connections of that Circuit. If its a lighting circuit check all wiring to the bulbs , the bulbs and sockets to find the shorted aspect in the circuit. Move wires around to see if the light on the tester goes out.

Look online to find out how to do a Parasitic Battery Drain test. A multi meter that measures amp draw is better than a 12V light.

The only difference between the two is the multi meter measures the draw and the test light just shows a draw. The amount of the draw is seen in the brightness of the test light. Either way the draw is seen. Better or worse both will find the problem circuit