Just about a week ago, I came out to my car after going to the store one night, and I saw that my headlights were on. I thought I must have forgotten to turn them off before going into the store, but I get in the car, and the switch is turned off. It's the low beams that are on, but they're on really dim.

So I start the car and turn the low beams on with the headlight switch. Now only the passenger side low beam is on, and it's at the normal brightness. I asked a friend what the problem might be, and he said probably either the headlight switch or a bad ground at the battery. I checked the battery terminals, and they're all clean, but I saw some corrosion down at the bottom of the battery tray where the negative cable attaches to the tray. It looks like the white/orange leakage you get when you leave batteries in an electronic device for too long. Could that be my problem?

So now I've been having to unplug the negative cable whenever I park the car so I don't run the battery down. BUT, now the car has been doing something different every once in a while. Here are my 3 different random scenarios now when I park the car & turn it off:

1. both low beams stay on very dim
2. passenger side foglight stays lit at normal brightness
3. all lights are off just like they should be

Also, whenever I drive at night now, I only have the passenger low beam lit at normal brightness. I was thinking the driver's low beam might just need a new bulb, but that bulb is dimly lit sometimes after I turn the car off so the bulb can't be dead. Does anyone know what the problem could be? Any info would be greatly appreciated.

Sounds like a bad switch. Might have a bulb,or two out as well.

Can a bad headlight switch also affect the foglights?.......because sometimes that passenger foglight stays on.

I would check the fuses...

I don't think a bad fuse would cause the headlights to stay on while the vehicle is off, but I have seen it cause the headlights to be extremely dim...