Need wiring diagram for true t49f

Most all true units have digrams on the unit. May have to pull covers to find them

2 and 4 are power for the timer 1 and 3 are load lines N is defrost termination.

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all of the time otherwise the doors sweat.

There is a switch above the door; check you have power from it when closed, then check the evaporator is cold enough as there is a thermistor that stops the fan until it is beginning to freeze. Lastly check the fan blade isn't stuck and the motor is ok.

Probably the compressor has shorted.
99.999% of the time this is the main culprit.
Otherwise wiring short.

as a general rule, in ALMOST every case, the thermostat just breaks one side of power. Usually one wire in and one out. I've not seen a double pole, single throw in a True, ever.

Is there a reset switch on this True freezer

First of all the unit uses a low temperature compressor which is designed to work on a freezer. Refrigerators use a medium temperature compressor. So most likely it would be over sized for what you are trying to accomplish,
Secondly the evaporator feed device is designed for "low temperature", not "medium temperature", so it would involve resizing the feed device.