Headlights not working

Please chk the headlamp control assy lever.

If low and high beam both are failing to work check the ground for that side . If high or low one works and the other does not check the fuse for that beam as it has 4 fuses one for each side and low and high. The fuses are in the underhood fuse block . Marked as LO HDLP LT, HI HDLP LT, LO HDLP RT and HI HDLP RT . They are 10 amp fuses .

check for a damaged wire for the low beam. Also wouldn't hurt to check the ground wire as the high beam will try and ground through the low beam but not visa verse

There is a headlight relay in the engine compartment fuse box, but its after the headlight switch and before the dimmer switch, so it powers both high and low beam circuits.
I would check the dimmer switch.

i would try replacing those bulbs,the headlights are dual filiment and can work on just high beam and not on low beam,so start there and replace your bulbs

CHECK THE FUSES TO THE LIGHTS,CHECK THE HEADLIGHT SWITCH,SOMETIMES IT ACTS UP AND OR NEED TO CHANGE THE SWITCH, CHECK WIRES TO AND FROM THE LIGHTS

Fuse 22 and fuse 23 are left and right low beam headlamp fuses located in the PDC. 23 and 24 are high beam fuses. There is also a low beam and a high beam relay in PDC as well. If no headlights work I would check for main switch or multifuction switch (wiper/high beam) since each light has its own fuse and relay.

Headlight Switch itself If Not then this Very Well May be in your Multifunction Switch

It sounds like it's your Headlight switch has gone bad, I'm thinking that the high beams are the daytime running light which is the same as your High beams. 
If you go to Auto Zone or Parts Source, they have the replacement switch with step by step instructions. Try not to run your Headlights too long from your running light's. The headlight's draw more amps then the running lights and can melt the wire which can result in a short and worst a fire.
If you remove the headlight switch from the dash, check the orange wire for power, if there is 12 volts. Good chance's are that the switch is bad, common on the GM's.
Good luck and hope this helps. I believe they go around $70.00 or do what most guys do. Salvage Yard range from $10.00 to $40.00 and there also have warranty.

I would remove the remote start some cars wont register the remote start with the computer then the computer can do some crazy things its a biglist of problems it can do