The headlight has been replaced now going on the third time in the past 6 mo. I have used Sylvania this last time, and some extra OE bulb that came with the car. The headlight works great for a few weeks and slowly becomes weaker and weaker until it burns out.

btw its an 04 wagon.

What do I need to do?

Check the connector to the bulb contacts. There may be a bad connection there and the bulb contacts are getting burned.

sounds like the bulb has a bad ground. Usually a burned connector at either the bulb or the body ground.