2006 ram1500 my left headlight will not work on low, high beams and driving lights are fine

If your vehicle is 4 years old, I would suggest replacing both left and right headlght bulbs. It appears that your low beam filiment in your left light bulb is blown. I am assuming the wiring to the light socket is OK. Your local auto parts store can help you with this and sell you the correct bulb type for your vehicle. The bulbs are accessable behind the light assembly. The socket the bulb sits in can be removed from the rear of the light housing by turning it counter clockwise and pulling out. Replace the bulb. Don't touch the new bulb glass with your hands, but use a clean towel as not to get any oil on the glass. Rinstall bulb into socket and place the socket back on the light housing and turn it until it locks. Hopfully your truck is friendly and you can reach behind the light assembly easy.

Hope this helps.