Hey dude, very difficult to say without knowing more about it.
The headlight switch controls all 3 circuits of lights (park, low b eam, high beam) on different circuits. As far as I know the body control module only has a park light input so it can dim the radio and dash etc when they're on, so I'd doubt iit is anything computer related.
The headlight switch controls all switching.
Firstly, I'd check that all the globes are the correct type and installed squarely and of the right type of globe (1 pin and 2 pin etc) I've seen this a couple of times.
Then you need someone skilled with a multimeter to check the switch to see if voltage is at the right wire at the right switch setting.
Have you done anything to the car lately? ie replaced globes, fitted any electrical accessory, fitted new lights of any kind?
