All my lights are on all the time. headlights, running lights, tail lights. During the day, in park (when engine running), even when the car is off, but the key is in the ignition. The only thing the switch does is turn on the dash lights. Is there a way to shut them off when not needed?

 

They shouldn't be on at all when the vehicle is off... Something is definitely amiss with your electrical system.

Are there any aftermarket electronics on the car (alarm, remote start, etc) that may be affecting their operation?

Have you tried replacing the relays (there are 3 of them) for the headlights or putting a resistor in the light sensor on the dash to turn off the automatic headlights?

 

Not aftermarket stuff, but I will try replacing relays. Thanks for the info.

 

My '01 did this once, IIRC. There were B or U codes stored. I cleared them with a Tech2 and everything worked normal after that.

 

A miscommunication problem with the BCM could cause the condition as well. You will need something better than the run of the mill generic scan tools to pull codes from the BCM though.