My AC was only working on 4 and 5 last night is stopped working, could it be the on 2003 Chevrolet Silverado 1500

blower resistor or maybe a fuse Thanks

Check all the fuses first. If they are good, pull the blower resistor module out and check it for burn marks or melted/bubbled plastic. If it is good, it could be a bad HVAC Control Module, but you will need a scan tool (not just a code reader) to check that. Also check the power and grounds into and out of the HVAC Control Module.