No AC

This isn't going to be helpful at all, but that never stopped me before. How did you get this far without knowing how your truck works? If I had anything useful it would go here, but I don't so this is what's here.

 

Sounds like a mechanical issue if it's throwing in hot air unless it's hot outside. It's just going to pull that warm air in. Honestly, let dispatch know and then talk to safety. Make it all about your safety and perhaps they might give you a different truck. Worth a shot. If not you might just have to deal with it for the time being until you get a bit more experience.

 

If they have an after hours maintenance line I’d be ringing them up. No A/C this time of year just ain’t right.

 

Okay so until you can get ahold of someone sit in the drivers seat and push the brake pedal everytime you get the warning and put that Air Conditioner to max to try and get it as cool as you can. Once you feel it's cool enough let it shut down. Rinse and repeat once it becomes too hot. Use the fan to help circulate the cool air better.