No AC on 2003 Suburban

[MASTERBrian]

The AC was blowing cold yesterday on several trips, then towards the end of the day everything changed and it only blew hot air and it's about 100*+ outside.

I hooked up a DIY gauge kit but it didn't seem to accept the freon, so I stopped. On Friday I plan on taking the truck to a friend that is AC certified to have him look it over and hook his gauges to it, but curious if anything I should check in the meantime.

I pulled and looked at the fuses, not the relay under the hood though, and all looked ok. I did not ohm the fuse to insure, might do that in a few. I do question the climate control switch as it looks like maybe it is grimy looking. Is there an easy way to test this?

My friend mentioned maybe the belt was thrown as they are common issue, but it looks intact and is spinning and isn't that old, maybe 20-30k miles.


****I'll add in the fall I had issue with no heat and that turned out to be clogged heater core, I had the system flushed and they said it was pretty bad and might need it again to clear it all up. Any chance that issue could have returned and that it's that time again? Or would that mainly affect the heating cycles?

This also affects both front and rear systems, the heat loss issue earlier was only the front heater core, so the rear system remained working. The blower works fine, I think all actuators are operational. It did seem at times as though maybe some cool was trying to come on, but it wasn't strong like normal operation, just maybe some cool. Hard to tell when it's that hot out.