OK you have a Dometic DM 2852 model fridge.
That fridge has a factory pre-set thermostat (non-adjustable) for temp control.
The thermistor can affect overall temp in food section by it's location on right hand fin in food section (4*F-6*F affect).
Sliding it UP will cause fridge controls to run longer making food section cooler.
Sliding it DOWN will cause fridge controls to run shorter making food section less cooler.
IF it is NOT attached to right hand fin and laying down on drip tray or hanging down loose it will cause fridge controls to continue to operate (due to lack of proper sensing) which can freeze items in food section.
If the thermistor fails it will also cause fridge controls to continue to operate freezing items.
SO YES you have a thermistor.......
Also that model of fridge has the optional fan mounted above absorber tank (mid position of fridge) in outside compartment to increase air flow (draft) across cooling unit. Fan is controlled by a thermodisc mounted on condenser fin (at top of cooling unit).
It would cause LACK of cooling if not working