Questioni have a 2000 dodge grand caravan sport, 3.3L flex fuel,
and the instrument panel is reading that a door is open, and all of the interior lights are on, even though all of the door is closed.
i have already tried opening all the doors and pushing in the switches to see if one of them is bad, and nothing changes. any ideas?
AnswerHi Sarah,
OK, so the rear hatch doesn't turn on the interior lights; and I presume that opening the engine compartment hood doesn't either. And finally that you haven't accidentally turned on the interior lights by manual switch on the headlamp control?
If that is the case, then what you need to do is remove the relay that I described which unfortunately will turn off all you interior courtesy lights until you have a chance to diagnose the problem (there is not a separate relay for each door, just a separate switch which activates a single relay controlled by all the door switches).
The door switches act by grounding a wire that comes from the body control module which is ganged together with the juntion block (fuse/relay block under the dash). They are attached together, back to back, so just find the junction block and on its back side will be the body control module.
That module has 2 40-pin plugs, both are natural in color. One is labelled with wire/pin numbers 1-40 and the other is lablelled 41-80. If you will pull the plug that is 41-80 out of its socket you can then do the diagnosis for which door switch is falsely open. You will need an ohmmeter or continuity testor and place one lead on the pin and one lead on a shiny metal body surface nearby to see if even though the door wire you are testing should not be grounded (e.g. show infinite resistance or non-continuity to ground) it is in fact grounded. Of course the door you are testing the wire for has to be closed. The left front door is a tan color wire on pin 79, the left rear door is tan/orange on pin 47, the right front door is tan/red on pin 48, and the right rear door is tan/yellow on pin 77. So whichever one of those wires is 0 ohms/continuous between the pin and a shiny metal chassis surface (ground) is the door with the faulty switch or a wire from the switch to the body computer whose the insulation has broken and touched a metal part of the chassis. If you can find the reason and fix it that is the best. If not, you can cut the wire near the plug and that will eliminate the false ground but then that door will never cause the interior lights to come on when it is opened.
That is the story.
Thanks for the generous rating and nomination.
Roland
Hi Sarah,
It appears that the switches that will turn on the lights include the four doors and the rear hatch (liftgate) so check that one too. If you can't shut off the lights then one temporary fix is to pull out the relay for the interior lamps which is located under the dash, on the fuse/relay box, it is the the one on the right end of the four relays located just above the row of fuses on the bottom edge. Then I suspect that one of the wires from the door switches to the fuse box is grounded someplace along its path. Do you have an ohmmeter? I can tell you which wires on the plug at that fuse box are the ones that come from the switches and you can check each of them to see which one is grounded falsely. Then you can either trace for that wire or if that is too big a job, just disconnect that wire from the plug. That door won't turn on the lights after that, but it would allow you to have interior lights again after replacing the relay.
So let me know if the liftgate is the problem and if not, then pull that relay and let me know if you want the instructions for figuring out where the falsely grounded switch wire is located.
Roland
