if in doubt about power issues IMO get new 9006 plugs, a good 40amp relay, inline fuse holder and some good size gauge wire and some crimp terminals.
if power is an issue like quite a few people have. it could be corrosion inside the plug or internally corroded wires running to the bulbs. either way could just not be getting enough voltage. with the relay setup you pull power directly from the battery terminal to a inline fuse, then to the relay. then simply use a wire tap connection of any type to the stock headlights power on the headlights ( light brown wire i think) and use that wire to the relays activation terminal. then give the relay its own ground, simply self taping screw and ring terminal crimped into the radiator support or what not metal (be sure to scrap off the paint for best connection!) and also add grounds there to go to the new 9006 plugs for grounds. then the output from the relay to your new 9006 plugs power into the bulb. and your done! add wire loom, electrical tape over any exposed terminals and what i like to do is put a zip tie over the wraped areas as well to keep the electrical tape from coming off in the heat softening the glue. the zip tie keeps it from ever coming loose!
http://www.the12volt.com/relays/relaydiagram25.html
this way you simply bypass ALL of the weak power source problems! the relay needs very little power to activate it so typically no matter how weak it is it should still work great! you could also just buy some HIDS and a headlight harness kit which is basically the same thing i described BUT add the HIDs for even more light output
but costs more. but it i believe is more plug and play besides the power and ground connections i believe.
