I purchased a set of LED bulbs for my 2000 F150, and when I plugged them in, they barely light up. WEIRD!!! Never seen that before and I have installed a few sets before!! I bought them from Amazon, so just returned them until I can find out what would possibly cause this. I put the original bulbs back in and nice and bright again. Well, nice and bright as halogens can be....I didn't do any voltage tests because the original bulbs work fine, so I could assume the voltage is correct. I also turned the headlights and fog lights on same time and they all operated with original bulbs in. Kinda stumped!!.

 

probably just a bad set of led bulbs from china

leds also suck in halogen housings and blind other drivers.

run sylvania silverstar zxe gold 9007 for halogens