GMC Repair: 99 GMC surburan, low beams, high beams

Question
the headlights dont appear to come on when the switch is turned to the full on spot. when i start the truck the day time running lights come one with no tail lights. when the lights are turned to the park light spot the low beams whitch i think are the day time running lights are on and the tail lights and the rest of the lights are on and if i click the dimmer switch nothing changes no brights. when i turn the switch to the headlight on spot the low beams (day time running lights) turn off and i only have park lights and the rest of the lights but if i click the dimmer switch the high beams work.

Answer
one of two things, 1st strangely enough you could have two burned out low beam bulbs, it can happen, or the switch is bad.  The high beams are also the daytime running lamps, they just do not run as bright when in DRL mode.  Also it may have a fuse for the low beams and if it is a luxury model it may have a headlamp controller, good luck