2007 chevy malibu

I don’t know if this has anything to do with my problem but this is what started. My battery died a few days ago. I got it changed at a retail auto shop , no problem. However as soon as i left the parking lot , not even 100 ft down the road , the A/C goes out. no cold air at all. Now even with the a/c off and all the vents closed it’s still blowing super hot air through. The car doesn’t over heat to where i have to pull over but if i drive it longer than 45-60 min straight the heat signal thing goes higher than it should. (sorry i know nothing about cars or car parts.) Could the guy that changed my battery have screw something else up? The coolant level is full too. i don’t know of that helps? is it the radiator , hoses? i have no idea what i’m looking for when i open the hood. please help!

not likely that he did anything as the battery isn’t even close to the systems that affect your blend door switch.

you probably have a malfunction of your switches for the fan. bring it in and it will likely be an easy fix.

well easy fix is okay , costly fix is what i’m worried about

Check to see that your radiator fan(s) are coming on. Pop the hood - turn on the AC - see if the fan(s) are turning. They should always be on when the AC is on. If not, the wiring/ connections to the fan may have been disturbed when the battery was changed. They’re not far apart. This would also explain your temperature gauge (heat signal thing) being higher than normal.