Strange problem

[ggtsvnv]

Sorry if this has been covered, I did a search and didn't find what I needed. I was driving my 87 1/2 ton 2wd S/W truck. I turned on my headlights and the low beams didn't work, so I clicked the dimmer switch to high beam and the all four lights came on like they are supposed to for the brights. Then I was pulling a trailer down a steep grade just creeping along and shifted the trans (auto) into low gear. After I got down the grade I shifted the trans into "O" and the shift indicator didn't move, it stayed in first. Then my head light dimmer switch not longer clicks from high to low beam. Could the two be connected somehow? Or is the dimmer switch and indicator related? I was thinking that my low beam lights burned out because one was not coming on all the time, but with the indicator and dimmer not working I'm not sure. Anyone have any good ideas as to what too check?
Thanks