Which Brand/Model is this fridge......????
Generic help
Inside the food compartment is a temp sensor (thermistor)
It is held onto one of the fins by clip. It senses the temp of the fin which the fridge thermostat controls uses to regulate the cooling cycles (turn heat source on/off)
If Dometic it will be on far right fin'
If Norcold typically on the 10th fin from right
In outside compartment is the 'control module'
Unplug 120V AC power cord, 12V DC leads etc to remove cover on module.
Then unplug the 2 leads for the thermistor
Replace cover and AC/DC power leads
Turn fridge on and run overnight......w/o thermistor plugged in the fridge will cool continuously. Freezer should get down to 0*F and food compartment should reach 38*F or lower.
If it does..........bad thermistor.....replace
Provided you do NOT see any yellowish powder/residue when you inspect around burner area as mentioned in above post