Door locks, auto headlights, and dash lights problem
Thursday morning when I got into my truck to go to work I smelled a strange electrical smell but didn't think anything of it. Later that day, I tried to unlock my passenger side door with the keyless entry, but it didn't work. I went inside and tried using the button on the driver's door to unlock it, but it didn't work. While I started to take off, I noticed the truck didn't try to automatically lock the doors like it should. I then tried to lock them myself, but it didn't work. The only thing that does work is it will UNLOCK the driver's door. That's it.
Another thing I noticed that stopped working on Thursday is the dash lights when you have the headlights set to AUTO. If you turn them on manually, the dash lights work fine.
Does anybody know what could have happened and if it can be easily fixed?
Probably a short in the instrument cluster, just got my wife's 06 expedition out of the shop for the same thing, auto lights wouldn't work, worked fine manually, radio would not turn off with the key removed and the door open, A/C blew but compressor would not cycle to get cold air, interior lights wouldn't come on when you opened the door, etc... The mechanic said he would have bet his paycheck it was the body control module.
Mine's a single cab 4x4. Where is the box located?
No one answered this? I don't know for sure, but can't help but think it would be mounted in the back of the cab just behind the seat back. But I'm worried about that electrical smell you had. That don't sound good right there.
I had weird electrical problems with the Expo and read somewhere here that the windshield seal will leak and water will drip on the ECM, which should be located by your left foot under the dash, possibly behind the plastic cover. Have you had rain lately? My windshield was cracked anyway, so I had it replaced and we have not experienced any of the electrical issues since.
One thing you can check is to make sure you didn't get moisture in the fuse panel where it started corroding. You might have to disconnect the battery and then pull the fuse panel off its mounting location to see behind it. I've seen posts on here before where water has wicked in from under the hood following the harnes through the fire wall and gotten into the fuse panel. You said you had water on the floor of the passenger side.