Product review (5 stars): Worked
On Norcold model N300 fridge, the thermocouple wouldn't keep the pilot lit. First suspect, as always, was the thermocouple. Looked at the thermocouple through the back of the unit and noticed it was not correctly threaded into the interrupter. The threaded inlet on the interruptor wasn't deep enough to fully engage the threads of the thermocouple fitting. I purchased the new thermocouple and attempted to install and wound up with same problem - fitting wouldn't thread properly into the interrupter. I could only just barely catch the first thread of the thermocouple fitting with the threads in the interrupter. Fitting was inserted as far as it would go down into the interrupter inlet. Needless to say, problem not solved by new thermocouple. Began to suspect someone had used the wrong interrupter at install or previous repair time (I bought the trailer used). OK. More research. Ahhhh...apparently there were several fridges manufactured by Norcold using connectors made of material with with too high resistance factor to be able efficiently carry the few milliamperes generated by the thermocouple through the valve control system. To fix this Norcold created a replacement wiring harness that consists of just two wires (red and blue) and their connectors.

For details see Norcold Service Bulletin N300 LP Mode Troubleshooting TNCSTP 081804
Here: http://comet.ak.planet.gen.nz/~matelec/PDF/n300_lp_bulletin_081804.pdf

I ordered these wires with their connectors along with a new interruptor (Norcold Inc. Refrigerators 621737 Thermocouple Interrupter) and it all installed easily, the previously purchased thermocouple threaded right into the new interrupter, and the fridge now works fine. By the way - depending on your particular circumstances, you may not have to take the whole fridge out of the cabinet to replace the wires. I was able to get my arms past the cooling fins on the backside and work it from the outside access on the trailer. It helped me to wear long sleeves as I pushed my arms up and over the cooling fins - the corners were scratchy. Be careful when you pull off the connector going to the flame meter when you replace the interrupter, that wire is tiny gauge and you don't want to give the connector too hard of a pull and end up yanking the wire out of the meter when it finally lets go. I think I came close on mine,

In the end I can't know if it was the thermocouple or the interrupter or the wires and connectors, but replacing all three components has, so far, solved the problem. We took it on a three day jaunt right after installation and it worked fine the whole time.