Thermistor placement

[Fugitive861]

Assessing our motorhome’s refrigerator I noticed that the heating element would kick off when the internal temp was around 40 F. I researched and found a table and checked resistance of thermistor as described by Dometic and values were appropriate at several temperatures (in cup of water). I moved the thermistor to the far right, upper portion of the cooling fins but still the element would kick off at around 40F. The thermistor gave resistance reading equivalent to 28-30 degrees as the fins were somewhat colder than the rest of the vault. This is with selector on coldest setting. I moved thermistor off cooling fins and laid on top shelf. Refrigerator cooled to 27F. I took off coldest setting and selected next warmer setting and now it maintains about 32-33. I run fans on the cooling fins inside and exhaust fan on outside. It seems to work well with thermistor on shelf...not on cooling fins as described my Dometic manual. Has anyone else experienced this?

[Kahoona]

I found the same with our last Dometic. I don't think they are normally that way but when they are "off" a bit that works.

[Old-Biscuit]

Moving the thermistor UP/DOWN is a means of affecting temp control (thermostat) on those MODELS that use 'AUTOMATIC TEMP CONTROL'


Those models that have temp settings (1-5 & 1-9) the thermostat control temp range is calibrated/based on OEM position of thermistor on specific FIN

FIN temps are ~10*F colder then compartment temps


Disconnecting themistor from fin and laying it on the shelf or hanging down etc will cause very cold temps in food compartment because thermostat has NO feedback of temp so it OVERCOOLS


Althought your thermistor 'tests' good........it is NOT functioning properly
You need a new thermistor.

Unfortunately the thermistor wiring is difficult to replace.
Fortunately there is a product that allows for replacement if just the temp probe......with rheostat that will allow minor temp tuning (6*F-8*f)


Snip-The-Tip
https://www.snip-the-tip.com/cgi-bin/articca.cgi








You stated with thermistor on shelf you moved temp setting from 'coldest' to one DOWN

Your old 1999 vintage fridge cooling unit is slowly dying
Otherwise with internal, external fans on no thermistor temp feedback the food compartment should be less then 32*F on 'warmest' setting (freezer temps should be 0 or lower)


20 yrs is pretty good service life for an RV Absorption Fridge