Q: Interior lights turn on and off when my jeep is turned off and all the doors are closed, how do I resolve this?

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I bought a used jeep from an auction a year ago and it has had a battery drain issue since the very first day. Me and my dad have done everything to find the source of the drain but it still eludes us. However I noticed the other night that the lights on the inside of the jeep were coming on and shortly turning back off over and over again. The car is completely turned off, all the doors are closed, and the light switch is set to turn on when the door is open only. I'm not 100% sure this is the exact cause of the battery drain but it seems like it would be, what is causing it and how do I fix it?

Hi There, I would suggest having the alternator checked to determine if it is receiving the proper amount of voltage from something called the voltage regulator. The voltage regulator regulates the charging voltage that the alternator produces, keeping it between 13.5 and 14.5 volts to protect the electrical components throughout the vehicle. The voltage regulator controls the field current applied to the spinning rotor inside the alternator. When there is no current applied to the field, there is no voltage produced from the alternator. When voltage drops below 13.5 volts, the regulator will apply current to the field and the alternator will start charging. When the voltage exceeds 14.5 volts, the regulator will stop supplying voltage to the field and the alternator will stop charging. This is how voltage output from the alternator is regulated. When the voltage regulator is not working properly, this may cause the alternator to allow the power the alternator supplies to drop resulting in the battery dying again. The other possibility may be condensation getting inside the lighting control unit, which controls the functioning of the interior lights, which are also partially controlled by sensors that indicate when the doors are opened and closed. I would suggest having a professional from YourMechanic come to your location to diagnose and inspect your vehicle.

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