Not nearly enough information to be of any help. I am assuming you have a small continuous run, 3 way fridge installed in most pop-ups.
Below is a photo of what the install looks like on my A-frame. Behind the upper vent are the switches for 120V AC (green), 12V DC (red), the knob to adjust the AC (not all PUP fridges have this), and the wall receptacle where the 120V part of the fridge plugs into. Behind the lower vent are the propane controls - on/off switch, knob to adjust gas flow, and igniter push switch. In the photo, the fridge is on DC. The AC and propane switches are off.
Only one mode can be on at a time. Some fridges have electrical or mechanical interlocks to prevent more than one mode being on at once, the one in the photo does not.
So for operation on 120V, AC switch must be ON. DC and propane switches are OFF. I usually set the cold control to max for the first 12 hours, and then adjust once the fridge is cold. When the fridge has been on for 30 minutes or more, the "chimney" (the round insulated vertical tube) should be warm-to-hot to the touch. You should feel hot air coming out of the upper vent.
If still not cooling, the newer PUPs have all (or most all) AC outlets controlled by one or two GFCI outlets. I'm not sure this was standard in 2001. The GFCI that controls the fridge outlet could be tripped, and needs to be reset. Also, the AC circuit breakers on the converter front panel should be reset.
Finally, loading a small PUP fridge with warm beverages on a hot day - it's going to take 24 hours for the fridge and contents to cool back down to a reasonable temp, even if the fridge was already cool. If possible, always pre-cool stuff before putting it in a PUP fridge.
I did buy a $10 battery-powered wireless outdoor thermometer from Walmart to help me monitor my fridge. Put the sensor in the fridge, and read out the temp without opening the door.
Hope this helps
2014 Rockwood A122 A-frame