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Interior Light Timer

Greetings helpful and knowledgeable mechanics.
A one year old battery on our 2005 Grand Caravan will not start the van after a door has been ajar for more than 30 minutes. Sam’s hand help battery tester says the battery is fine. We have two issues here: Why does the battery lose voltage so quickly if the battery is good? And why doesn’t the interior light timer turn off the interior lights after 15 minutes as the operator’s manual states? Can’t find anything that looks or says it is the interior light timer in the fuse center under the hood.

I’m not sure what kind of battery test you used, but the only valid battery test is a “load test”. Good batteries will lose some voltage with a door ajar. How much depends on how much current drain occurs when the door is ajar. That can be measured with a “parasitic drain test”. Those two tests are probably the first steps in getting to the cause of this door ajar/no-start problem.

As far as the interior lights, just a guess, but if the door is ajar the light may be designed to stay on indefinitely; i.e. only when the door is completely closed does the light timer work. You’ll probably have to stop by a dealership and ask someone there if they know the specifics.