1997 deville, battery drains overnight,pin pointed to a relay in trunk energized, removed relay, no dash lights.if you remove body 3 50 amp fuse it doesn't drain overnight, but also won't start without it. not sure if there is a fuse in trunk that can be removed without loosing dash display.any suggestions.

The light is on because the system fuse was removed, this causes the control module to see a fault. either fix the system or pull the dash and remove the warning bulb.

Is the red light in the center of the dash , on top of dash panel not instrument cluster flashing when trying to crank the engine over ? If yes you have a anti theft system problem ! If the light is not flashing you can check for power an ground an PCM control at the starter relay in the under hood battery junction box ! Bottom of relay or side show pin numbers ! Pin's 30 & 86 should have battery voltage ! Pin 87 - ground through the starter , Pin 85 should have nothing unless cranking engine over . The PCM supply's a ground here energizing the starter relay ! You can also test this by using a test light . The clamp end to battery positive , the point end touch to pin 85 relay socket while cranking ! Test light should light !

Remove a battery terminal, Connect an Amp meter in series, should get a reading of about 0.3 of an amp, that will be the clock, for it to kill a battery overnight I would expect a reading of about 3 amps, something is staying on? Trunk light is a favourite, you can't see it with the trunk shut, remove the fuses one at a time and watch the meter, when the drain drops off, you have found the cicuit

unhook neg batt cable install test light between cable end and batt terminal if light is on you have batt drain pull fuses untill light goes out thats the circut thats pulling down your batt remember where each fuse goes also clock and raido fuse should be pulled first

when you have a problem such as this, i would try to unplug the amp over night and see if any thing changed. also you can take a 12 volt test light and remove positive battery lead. then hook up the test light in series ( the wire end with clip hook to cable that's off . and the pointed end for checking curcuits. goes to battery post. the post you removed cable from .the test light will illuminate.it will be bright if you have a large drain on this system.it should have a small drain for the memory for the ecm in the car. then start removing fuses until the test light goes out or dim.try to leave the amp unplugged during this test. maybe this will help!!

You should have a switch in the trunk area or on the trunk latch it makes contact to ground to turn on the light in trunk if you disconnect the switch should take care of it temporarily.

If the trunk is 'open' ... there is probably a light in the trunk and the light will kill the battery over night ... yes. Adjust the switch to fix this problem.

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This should be done with everything turned off and the door closed. with negative battery disconnected. place 12 v test light between the battery terminal and the cable end.(on neg. side) if the light lites up there is a drain. remove one fuse at a time until u see the lite go out. that is the sytem the drain is on. usually glove box light or trunk light or visor light left on or stuck on.

I stated "such as a light " there are many, many other causes of 12 volt drains such as a seat switch that might hang up and stick. Empty that battery overnight. First install a 9V Battery Radio memory / and clock or you will have to reset both. Disconnect BLACK negative cable of battery. Using a 12V testlight, connect one end to the disconnected cable, and the other to the negative battery terinal. It should light. Remove the 20A BODY and LIGHTER fuse first . This will eliminate the courtesy light circuit . If light goes off the drain is on that circuit. STILL LIT ? drain is on another circuit. Start by eliminating fuses. Hope this helps.

well for starters there is many factors at play here. 1. battery chargers need to be on and battery disconnected. make sure if it has a timer it did not run out and (the charger may also have an internal fues/ relay ) if it gets too hot it shut off. Was the charger on a high enough setting to compenstate for the drain and is your battery good enough to be charged even. constantly drained batteries will actully not hold a charge after awhile. most parts or even walmart can check batteries free>
The trunk lights and fuel door on the same fuse? otherwise I would say the trunk has a bad switch that is not making contact or is making poor contact and acting as the trunk is open. it may just be pinched wires that rubbed together make contact with your cars steel body. They may be seen in the trunk follow the wires from the release switch and see if it connects anyplace near the fuel door. I am sure it will.