Refer not cooling on AC

Not sure about yours, but every two days my NoCold 1200 goes into a defrost cycle and the temps will raise 10 degrees for six hours. I can turn the unit off briefly every two days so it does not know it's it's time to defrost. By moving the fan on the fins inside I can keep them from building up with ice so no defrost necessary.

OK. glass fuse is good, 45 ohms at the heater leads. Maybe it just got to hot!! Chino

Got 110v at the plug. No fans on this model. Refer 8 months old. Thanks for the tips! 110v and propane only. Chino

You have to pull the circuit board cover to get to the 110V wires going to the heater element. You have to pull the two wires from the board to check the resistance or to put 120V to it BUT once the cover is off put it back on AC and check how much voltage your have on the heater element wires. If you have 110+V then unplug from AC and remover the wires from the board and check the resistance...44+/- ohms. If more than 60 ohms I'd say the heating element is going bad.
Doubt your 8 CU Ft refer has a rear fan, but if it does, are you sure it's working? If it is in a slide out then you may have a fan that's not working.

Stop.......

First thing is to check 120V AC outlet fridge is plugged into......does it have AC power? (that is all that outlet does....supply AC power for electric heat element----everything else uses 12V DC)

IF outlet has AC power......
Then you need to check 5A glass fuse on circuit board. It is fuse for the electric heat element. If blown....no AC power to electric heat element.
And if blown element is probably bad/shorted.

Electric element.......
You can check resistance. Unplug element leads from circuit board and then with meter set to ohms measure resistance thru element. 44ohms element OK

YES you can run element directly.
Unplug from circuit board and connect element leads directly to AC power
This bypasses circuit board and runs element continuously.

Your problem is probably a bad element vs board etc.-------s/b 325W element.
Easy to replace...just unplug from board then pull out of tube (might need to wiggle back/forth) install/connect new element.

"Hot wiring", or connecting the element directly to ac power is used to troubleshoot no cooling, but your is working on lp.
You just need to make sure it's getting power to the plug, check the 120 volt fuse, check if 120 volts is going to the element, and the resistance of the element.

If the unit is shutting the lp off, it is getting power and most likely the element is burned out- it should read ~44 ohms. If it isn't switching over, it is a power problem.

I'd start and make sure you have 120 volts at the plug the refrig. is plugged into. If you have power there at the plug I'd then check the 120 volt heating unit to see if it was burned out. You can do this with a test gauge just unplug the two wire and see if you have continuity between the 2 wires. If not you have a burned out 120 volt heating unit.

Those electric heaters are 120V on my Norcold. I strongly suggest you download a service manual. You start direct wire something it could directly effect your rig, e.g. fire.

You could have a bad 12V heating element,I personally would not by-pass the board. 12V on the reefer does not usually do a very good job of cooling and it does take about 10 amps (or more) 110 V or LP is best with LP being the better of the two

Does the AC heater feel warm/hot to the touch?
Is it getting AC power with a tester?