As a guess both low beams are burnt out
The daytime running and high beams are the same light filament.
Or the fuse or the relay for the low beams.
Your computer brain in your truck is messing up take it to a mechanic is my advice. Not sure I even understand what you are asking,but, If its what I think , its just a matter of turning on your lights. For some reason Chevy thought it would be a good idea to have just your low beams and the high beam dash light come on automatically when it got dark, don't ask me why. If this is not it rephrase you question and be more presice.
Yes
dimmer switch wore out or you might just have running lights.
Bad bulbs Bad dimmer switch
Have you checked the drl relay?
On my 97 Chevy Cavalier the daytime runnings lights are the Hi beams (brights). Have you replaced any of the bulbs? Yes, same bulb. This means your headlight wires are corroded and BOTH headlights lost the ground, so the circuit is open. The wire harness runs in front of the radiator. Pull off the cowl as if changing your headlight bulbs. The inspect the wire harness for corrosion (green-blue grainy spots). Repair the corroded wire by cutting out the corroded part and bridging the gap with a new piece of wire.
High and low beams have differant filaments. You have to replace the bulbs.
1995 berettas and corsicas have generic daytime running lights no matter what if the switch is on your headlights will be on. (although it should be lowbeams). in 1995 Chevy didn't use a lower wattage for the daytime running lights. and so far i haven't found a way to by-pass them.
hmm as you ask what happened to high beams, i am going to assume that low beam works. id this is correct i would say that your low/high beam switch needs replacing
I would suspect the dimmer switch or "combination switch".
daytime running lights for chevys are automatic. you cant turn them off. all you can do is control the high and low beams.
Check all fuses and check for burn out headlights, high and low beams