Headlight auto on switch FRIED?? 99 Denali

[spydermann11]

My trailer lights shored out and blew a fuse on my 99 Denali. I stopped on the shoulder and found where I thought the short was occuring, taped it up for a quick fix, replaced the fuse and went on my way. A few miles down the road, the lights in the truck dimmed & the dash light went off. I turned the knob to manually turn the lights on and they came back on. The Auto light switch had burned out is my thought. No big deal, I can turn them on, but here is the twist. When it is daylight out and I turn the lights on, the bright lights work normally. Once it is dark, the bright lights will not come on.
I want to fix this. Any ideas?? Please help!!

Kevin.