Intermittent failure to start?

It has failed to start about 5 times in the last week. I think that when I put the key in the ignition the lights and guages don't function until I turn the key all the way to engage the starter. The engine turns over, fires, the lights and guages, activate for a second and then the lights go out, guages never get so they're reading and then I believe I see the dash dark except for the battery light and maybe the Lock in the upper left of the instrument panel. I then can repeat the process over and over. Sometimes I can wait a half hour put the key in and it functions fine and I can drive 50 miles with no issues. Got home today and tried another key and it was fine. Thought maybe the key was the issue. Then went back to original key and that also worked fine. Also when I work the air and fan I smell a hot electical insulation odor. A wire or module under the glove box feels hot. I bought truck used and don't have the manual. Will try and check codes tomorrow.