Courtesy lights stay on all the time, only go out by pulling fuse

I have done this before, put about a 10 amp charger on the battery. Pull the courtesy light fuse first. Look at the battery charger, it is probably charging several amps, pull one fuse at a time. When the charging amps drops down you found the fuse the controls the problem. I had a car several years ago that someone pulled the seat belt all the way out, somehow it was pulling a load and draining the battery overnight.

Hi Dennis,

Your courtesy lights are controlled by your Body Control Module (BCM). Normal operation is for the courtesy lights to stay on for 2-3 minutes after the door is closed, then turn off.If they stay on longer than about 3 minutes, then there are several possible causes:

1. You may have the "courtesy lamp override switch" in the overide position in the dimmer control on the dash.

2. you may have a door that is not completely closed. You need to check ALL of them.

3. You could have a defective door switch or dimmer control switch

4. you could have a short to ground in one of the door control switch circuits, causing the BCM to "think" that there is a door open.

The CORRECT way to fix this would be to scan your BCM for fault codes and also read the BCM data to find out if it is showing one of the doors as being open when they clearly are not, so you will know which door is causing the problem.

Removing the courtesy lamp fuse will NOT completely fix the battery drain problem if these circuits are shorted or malfunctioning because the BCM will STILL be "trying" to turn these lights on and this will also cause an excessive draw on your battery. However, removing the 15 Amp fuse marked "CTSY LMP/MIRROR" located in the instrument panel fuse block will get the lights turned off and at least slow down how fast your battery is draining.

START THE VEHICLE, PUT A VOLTMETER ON THE BATTERY. THE VOLTAGE SHOULD READ 13.90 TO 14.80. IF THAT IS OK, THERE MAY BE A BATTERY DRAIN. TURN OFF EVERY SWITCH IN THE CAR.CLOSE ALL THE DOORS. MAKE SURE ALL THE COURTESY LIGHTS ARE GOING OUT. & THE GLOVE COMPARTMENT LIGHT. RAISE THE HOOD. DISABLE ANY UNDER HOOD LIGHTS. DISCONNECT THE NEG. CABLE FROM THE BATTERY. PUT A 12 VOLT TEST LIGHT, ONE END ON THE NEG BATTERY POST & THE OTHER END ON A GOOD GROUND { METAL }. IF THE LIGHT COMES ON THERE IS A BATTERY DRAIN. NO LIGHT , NO DRAIN. IF IT'S ON, ONE AT A TIME PULL THE FUSES OUT OF THE POWER DISTRIBUTION BOX. IF THE LIGHT STAYS LIT, PUT THE FUSE BACK. DO THIS WITH ALL THE FUSES BIG & SMALL. IF THE LIGHT STAYS LIT, DISCONNECT THE ALTERNATOR. THEY CAN CHARGE THE BATTERY WHILE RUNNING, & DRAIN WHEN STOPPED.

You need to readjust the switch on your trunk door, or replace. To check it locate it, tape it down with duct tape and see if the light goes off. If not it's bad. If it does it means it isn't sticking out far enough to be turned off when the trunk is closed. The adjusment should be fairly obvious. If not you can simply unplug it which has the same result as turning it off.

im not to good electrical but i would say you have a bare wire touching metal or something. maybe a wiring glicth.

Have you tried the switch on the dash that turns them on? Are door switches adjusted properly?

It will most likely be the courtesy light fuse, or it may be marked interior lights, it will most likely be 15 amp.

Have you check the door ajar switch in each door?

There is a module called the delayed entry module, it keeps the courtesy lights on for about 30-40 seconds when the door is opened, by what you say that may not be the problem, without the load of the light bulbs the timer will not work in the module, this throws off many techs. Have you had the battery tested?? even if it is new it can have a problem, I put three new batteries from Kragen in my Corvette in 1 year, I also thought the system had a drain, but it was the battery every time, finally bought a Delco battery and never had an issue again.

pull the courtesy fuse temporarily and see if the battery still drains,if it does then it may be in the alternator