03 gmc sierra ac and heat stopped working no cruise control and service 4wd message comes on, also abs and brake light on dash.

[mnsam]

Got an 03 gmc sierra, stopped in town, turned engine off, had ac on previously.  Was noticing also recently when i have the ac on truck seems to lack power.  Got back in an had no ac or heat or cruise control, 4wd message came on.  Reset the computer with gas pedal three times to no avail.

 

Any ideas?  

Truck runs and drives still