I own a 2001 FordExpedition. My running board lights and my interior lights will not turn off once my truck has been turned off. I have tried sraying with wd 40. I would like to know what else I can do to get them to go out and stay out before I have to buy a new battery.

nice double post, and still no fuse stated.
now is fuses, (2 fuses? in car at once) or blew a box full.?
back up and read. the answer, ive done 1000s of theses.
cars, boats, planes, ships. 50 years of shorts, and more.

have alternator tested

TCM module failure - controls all the items listed available at http://store.allcomputerresources.com/202020dodatr.html

There is a "body control unit" that runs most of the interior stuff. It is up under the dash on the drivers side. For more info www.hmaservice.com ,sign up for free on the home page look for a tab labeled : shop. click on that. enter the year make and model, and start researching. this is the same info the dealer techs have access to. It has helped me greatly.

it is more than likely a short in the headlight switch. also try the dimmer switch on the dash for the dash lights.

Next to the headlight switch is a dimmer dial for the interior dash lights... if you turn it all the way up, the interior lights remain on... there is a "detent" on the dimmer. turn the interior dash lights all the way full on ...you'll feel the detent, then turn it down back past the detent a little bit...that should cancel the interior courtesy lights... wait a bit because the interior lights are sometimes on delay timers....
good luck let me know what happens.

yes there is a relay switch in engine compartment or under dash

water made path to ground making them work when not turned on..now no water and primary wiring for interior lights compromised (since before rain)...must find poor wiring and bad grounds and fix

Try pushing in on the tailgate while the lights are on.

My lights have had this problem for months. From time to time I try to fix it, but I have learned the following:

1. [EASY SOLUTION] After turning off the car and turning off the headlights, when I pull the headlight switch back (toward me) and then let go, the running lights turn off. [/EASY]

Extra information that I haven't figured out how to use yet:

2. Apparently the DRL bulbs operate through the high-beam bulbs; this is why you get the high-beam light when the DRLs are broken (or whatever) and why you can turn them off with the high-beam switch.

3. My wife took the car out for a fluid change once and said the mechanic pointed at a light on the car and said, "that bulb's out," and that if she fixed it the DRL's would work normally, but she forgot which light it was. He even told her what bulb it needed. I took it to the same place and no one knew what I was talking about.

I don't think about trying to fix this very often since I realized I could turn the lights off with the high-beam switch. I used to worry that that blinker was somehow draining the battery, but it never has (whereas I once drained a brand new battery just by leaving the interior light on all night). I hope I've helped!

-Monteith