[bstark]

Oh boy; Rick's query is sure timely and pertinent.

If you've zeroed in on a cooling unit without verifying board, thermistor, relays etc., are all functional; you could go through a rather labour intensive & expensive cooling unit replacement and still have a problem afterwards.

Fridges are very sensitive to a full 12volt integrity loss. If you're not getting a full 12volts to the board ~ that's the first thing to fix.

Control board, relay to heater element & solenoid packs are all 12v energized.

Thermistor resistance response can be verified across the leads after unplugging it and immersing it into a cup of hot water etc.. There was once a thread on here (06?) where the Ohms values for a healthy thermistor were given

Checking your heating element resistance can also tell you if the element is failing.

My rig with it's crappy Dometic RM 2620 used up 120v heating elements like they were gumdrops. I carried spares of all the items such as board, thermistor and multiple heating elements.

Got really good at manhandling those dang heating elements out of the rusty tubing on the side of the boiler, blood loss was minimal after the 4th or 5th such endeavour.

Do your homework vis-à-vis cooling units very carefully as some offer premium pricing due to using thinner wall tubing and that's a deal breaker right there. Look for units with proven history, thicker wall tubing, especially at boiler junctions and who ship with all required items such as thermo-mastic compound used to provide thermo bonding between unit and inner cabinet cooling fins.