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

asked by on July 16, 2017

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.

Was this answer helpful?
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Gas tank's fuel pump stops pumping fuel randomly. Both fuel pumps are new, gas tank is clean, and a new fuel filters were installed.

Hello. The first thing to check when you have complete failure of the unit is the power supply. If the wiring going to the pump is loose or has a short somewhere, the power wont be delivered or will be...

Van starts and then dies

There are several issues that can keep a vehicle from starting, such as mechanical issues like off timing, bent valves, lack of airflow in the intake system, lack of fuel pressure from a failing fuel pump, or possibly a lack...

Lacks power on takeoff 1999 Dodge Ram 1500

Hello - the combination of a lack of power from a standing start, and a poor shifting complaint may indicate your transmission is in "limp mode". This would cause it to take off in 2nd or even 3rd gear -...

Related articles

How to Buy a Good Quality Mass Airflow Sensor
A A faulty mass airflow meter can cause myriad problems, such as rough acceleration and idling, stalling and hesitation. It may be difficult to diagnose since the failure of a number of parts may mirror these symptoms. The same symptoms...
What Is Key-Off Battery Drain?
Many Many things in your car continue to work even after your vehicle is turned off – radio presets, security alarms, emissions computers and clocks are just a few. They continue to draw power from your car battery, and the...
P0300 OBD-II Trouble Code: Random/Multiple Cylinder Misfire Detected
P0300 code definition Random/multiple cylinder misfire detected What the P0300 code means Most vehicles will have 4-6 cylinders. Each cylinder will fire...