DM2652 too cold

[Charles Thompson]

My DM2652 is freezing everything, the fridge temp runs around 20 degrees. I have replaced the thermistor and the control board with no change.   Any assistance you could offer would be greatly appreciated.

Thanks

Dana

[Kirk W]

If the chill box is that cold it is probably in constant cool mode for some reason. The most common cause of that is a thermistor open or shorted. Have you done any measurements with an ohm meter? Checked any voltages? I suggest that you download a copy of the Dometic Service Manual and go through the troubleshooting checks.

It is pretty easy to tell if it is in constant cool by looking for the flame if on propane or with your volt meter if on electricity. 

Quote

MANUAL MODE When operating in the MANUAL mode, the AUTO mode indicator lamp (A) will be off, and the refrigerator will run continuously on the energy source selected by the control system. NOTE: The food in the lower compartment may be frozen if the refrigerator is left on “MANUAL” mode. STANDBY MODE . . This control system contains a feature that will continue to operate the cooling system in the event of a failure of a major operating component. If the control cannot read the temperature sensor and operate at the preset temperature, then the control will run the cooling unit like the MANUAL mode.

 

Edited April 27, 2023 by Kirk W

[Charles Thompson]

I replaced the thermistor earlier and the problem still exist.  So, I then tested the new thermistor and it tested good.  The old one was probably good as well. I will look at the Service manual.

Thanks Kirk

I will keep you posted.

Dana

[Wrknrvr]

   I would have thermistor as cold as the freezer is. Then put it in room temperature with the meter hooked up, and watch what the meter does. It has been years since I did that.

   There is a manual thermistor for testing refrigerator boards. I am not sure if they have them for your fridge.

   If that thermistor does not hook directly to the board in the rear of the fridge. There could be a problem with the wiring harness to connect the two.

   Now I am thinking it could be the eyebrow board for the temperature control of the fridge.

Edited April 29, 2023 by Wrknrvr

[Charles Thompson]

I have tested both the old and new thermistors and both have the correct ohm setting at different temperatures.  The thermistor does connect directly to the control board.  Also, the DM2652 doesn't have a temperature control like some of the other Dometic fridge (Pic attached).   

 

[Kirk W]

Have you checked to see if it is in the constant cool mode? It definitely sounds that way. It is possible that there is a bad connection via the plug connection of the circuit board but if that is not the case about all it leaves is the lower circuit board. Excessive cooling is nearly always the thermistor but if it is good then it must be the control circuit and it is all located on the lower circuit board. 

You may want to contact an RV tech to see if he has one of the PAL testers that the service manual refers to and see if he will check your board if you take it to him.

Quote

NOTE: The PAL tester will allow for proper testing of the integrity of the upper and lower circuit boards. PAL is available from your Dometic parts distributor.