Norcold 4104 3-way freezer works but not fridge (Tab 400)

TomCanada

The 3 way in our 2021 Tab 400 has been acting funny.  It has slowly gone from not cooling well (in fridge section) to not cooling at all.  Same on AC or propane.  Freezer however is perfectly fine.  I checked the thermistor in the fridge and it's reading fine - around 9kohms in 75 degree ambient, and drops when I hold it between my fingers.  I tried moving it to another fin in the fridge and there was no effect. What DID seem to help was removing the thermistor from the fins entirely and laying it while connected on the shelf in the fridge (if I disconnect entirely I get an error 13).  With that approach, it cooled the fridge overnight.  I then went back and tried another position on the fins and it went back to misbehaving. Anyone had a similar issue?  We are on a weekend trip tomorrow and if I can cool the fridge with the thermistor lying on the shelf in the next few hours I'll go with that, otherwise I have an ice block in the freezer to use the fridge as a rudimentary cooler though that might backfire if the fridge thinks it's already cold and doesn't even cool the freezer at that point.  Help!

If needed I'll call norcold next week but hoping someone's had a similar issue and has a proposed resolution..

TomCanada

Ok so I think I have solved the mystery of the wonky fridge this season.  Somewhat.  Maybe. The thermistor location was really just trying to compensate for poor cooling performance in sun/high ambient temps.  I therefore shifted my focus and started wondering about the fan shown in my manual diagram as I have never heard a fan run before.  Sure enough I found it tucked behind the fridge where you can't see it without a mirror/phone.  But now the question was - why didn't it run?  I found that by shorting the thermal switch (which is easily accessible on the top fridge fins in the back) the fan would turn on.  After some experiments, I found if the fan was left on, the fridge cooled just fine, even in hot summer temps!  At this point I could check if the thermal switch is dead, but I found even under its threshold (135F) that the fridge wasn't operating well, so I've decided to just run a rocker switch from the inside of the trailer to control whenever I want the fan on (warm outside ambient temps).  The fan is only drawing 0.15A which is 1.6% of battery per day if run 24 hours, so seems like a good solution for me. Especially since it's not really needed overnight in most cases.

Hopefully this helps anyone else with an underperforming 3-way Norcold!

Tom

Kellercarol

I previously posted that I have not been able to run my Tab400 3 way fridge on propane and a number of people said they had the same issue. It was fixed. If you go to the outside/backside of the fridge there is a round adjusting nut that is set by the factory. See yellow arrow. In my case it was set too low and the freezer worked but insufficient cooling made it to the fridge. Hope this is useful