My 2004 pontiac sunfires headlights malfunction

Does high and low beam not work?
if not its time to break out the multimeter and check the light switch that turns the lights on and changes it from low to high beam.

Corroded headlight connectors period

if you have to hold the switch so the high beams stay on then that indicates a bad/worn switch,you could have 2 problems the day time running light relay may have a problem with it.i would first replace the headlight switch at the base of the steering colume as by the info you supply its not changing to the high beam side without holding the switch in position.

First check the R/S headlight fuse in the dash fuse panel (left side), second make sure the R/S low beam headlight bulb filament isn't blown, both these scenarios will do what you are saying. The DRL's work when both low beam lights are in series, thus only 6v going to each bulb at reduced brilliance. The high beam is a totally separate circuit controlled by the multifunction switch. The DRL relay is controlled by the Body Control Module, grounded there, and it will also illuminate the service vehicle soon light. It could also be a bad ground at G204. Its on the steering column support bracket.

I just worked on a Pontiac Sunfire on a light issue. The driving lights are on a separate switch on a 2003 from the dimmer switch. Have you checked to make sure both low beam light bulbs for your headlights are not burnt out on low beam? Have you checked to make sure you have power to the low beam where the connector connects onto the bulb?

this could be a little more simple depending on the lighting outside. quite a few GM's with DRL will turn on the dash lights and tail lights automatically when it gets so dark outside. if it happens when it's completely dark out i would check the switch itself and maybe the relay incase it is sticking

If your getting power at the headlight wire harness, then it's going to be the bulb it self, but make sure your checking the right 12 volt terminal at the plug. There should be three terminals there, there is a ground, 12 volt low beam, and a 12 volt high beam. If both the low and high 12 volts are getting power, then it's going to be the head light bulb it self that has reached the end of it's life time since the day time running lights are always on which is the high beams. Good luck and check the fuse box under the hood by the battery. 

sounds like either a wiring loom is shorting across somewhere ??where ----best of british to finding it

You headlight lamp have a diffuser mechanism which allows it to flip between the hight beam and low beam feature of the bulb. In fact, you high beam will function even if the low beam is not working.

I would recommend the purchase of the new headlight lamp. It would cost you you any where from $15.00 per unit to get a replacement lamp

Pull the headlight switch and check for a burned connector, this will cause a poor connection and in turn dim headlights or no lights.