Ice build up on back wall of my beverage cooler is it normal

If evaporator starts to freeze up the ice accumulated serves as an insulator and the temps go up. If you turn it off and let ice buildup melt the unit will work fine again until it refreezes.

Check if unit has a device to prevent ice build up. If so, it is not working. If warm moist air is entering the area of evaporator coil, that could also be causing the buildup.

Most cases of ice build up can be traced to seals that leak humid air into the cooler. Check the door seal carefully using a fresh $1 bill. The bill should not pull out easily when the door is closed. If the unit has a self defrost feature it it is not coming on. Ice buildup inside a wine cooler is very rare. The cooler box should not reach 32deg in normal operation. Does the unit seem to run continuously?

Ice build up wil accor if the evaporater blower goes out and does not crculate the air. If you have the model number off the tag I can be of more assistance, with the mobel number I can break the unit componants down in a diagram

you have a door seal leak, the ice is from outside air getting into the cooler, you might also check for an air leak it the service door in the bottom back of the cooler.

clean your air filter located in the front of the unit dirty filters can cause ice build up

Inside the cooler is the evaporator fan usually right in the middle behind a cover. As it slows down you have less circulation and ice forms quicker and cooling is diminished. Sounds like it is going out.

The system is most likley working fine.
The problem is moisture in side the unit. It needs to be dry inside or ice will build up on the cooling unit. make sure the lid is fully closed also.

It should get cooler than that at least down to 33-34 degrees. Be sure you have air flow behind the unit, not pushed against wall. Feel for cold air coming from freezer to lower part just behind light bulb. If it is not turning off and defrosting they will do this as ice builds up and results in no air movement. you may want to remove the cover in the back of freezer and see if it is froze up. Or just turn it off and defrost and start back over the next day. The defroster timer may also be bad and it is under cover beside the light bulb.

The fan should blow air into the heat sink. The warm air exits the heat sink at both ends. (It might work the other way, haven't tried it.)

When you have ice in your cooler, you know the thermo-electric element is working well--it's below freezing!

Ice builds up because there is water in the cooler. For example, in humid weather, you open the cooler, some humid air gets in, and the cooler temperature condenses the water. You have to empty this water, either by tipping the cooler, or using a sponge.

You can easily defrost the cooler by unplugging it for an hour or so. You know it's time to defrost when you hear the fan blades making a racket because they're hitting something--a thick buildup of ice.

There is a temperature control knob on the back side of the ref. it is on the bottom by the compressor
Have you adjusted this?

clayfoot