How to troubleshoot walk-in freezer & chillers

The simplest answer is No. Chillers and freezers use completely different parts to work correctly. Your best and easiest thing to do is to buy a separate under counter freezer.

as the freezer section is working , It could be a thermostat for the fridge section
If you have some mechanical and electrical knowledge you could possibly do a DIY repair with a new unit from the service dealer agent spares
The only other option is to load the unit onto a truck and take it to a service agent for repairs

Check the defrost timer. Turn the small slotted knob on the side with a screw driver until the unit turns off. this will force it into a defrost check the defrost heater strip if it is getting hot then replace the defrost timer if not then check with a volt meter to make sure your getting power to heat strip. If you are getting power to heat strip but it is not heating up then replace the heat strip. also before you force it into a defrost check the defrost termination switch with a meter make sure you have power going to it and through it. It will be mounted on the evaporator coil a round therm o disk with 2 wires on it should be a red and pink one. If you have power going to it and not through it then replace it. This cuts power to defrost time if it gets to hot at coil during defrost.

Open?

Don't you just pull the card out and place it where you want it and push it in?

The cards have slots on the bottom to allow the cards to pulled out and popped back on.

Is the compressor running? Is the condenser clean and the fan running? Is the fan inside running? Is there ice on the coil? Those are the first things I would check after I check to see that the plug has power and the temperature control is turned on.

loose clamp on,thermostat sensing bulb (c and s)
check position and tighten.
Chiller tray out of position(s) check and reposition
God bless you

There is a switch for the light. If it isn't a mechanical switch where the drawers slide in, it will be a magnetic switch in the edge of the drawer

You dont have to reset it, you need to defrost it, the defrost element has failed and you have ice build up within the chiller plates, air cant pass through it due to the ice, I think you will find that food is starting to defrost and you will see a bit of ice on the back panel inside the freezer.
Defrost it for 2 days with door open, after that, should work fine for a week or so, very common problem.
Hope that helps, Russ

sounds correct to me.

bearings in motor bad(new motor) fan blade hitting ice build up many different causes for this