Hot End temp control shutting off

Hi I have one of those mystery problems. My TAZ 3 has been running fine, prints per g/m-codes.
All of a sudden the hot end temp shuts off when the 1st layer is finished. Some facts:
I am using Slic3r V 1.1.7. In the Filament Setting the First layer and Other layers temp are set to zero. (No Slic3r temp control). Manual pre-temp is set in Printrun that stays the same.
The target temp stays the same on the LCD display and on the Printrun screen. Everything runs normally until the 1st layer is finished and then the hot end temp starts to drop. LCD current displayed temp starts to drop.
Don’t know how far down it would go since it is still printing. The filament would solidify. I’ve scanned down through the g-code looking for any temp m-codes and haven’t found any. Even sliced the test part down just above the 1st layer to shorten the code list. Ran many test parts to see if anything changes. Only thing that changes is the drop in the hot end temp.
It has to be something in the printer firmware code. Maybe have to re-flash the firmware code?
I would appreciate any ideas.

You may want to test your hot end heater resistor resistance. With the printer turned off and unplugged disconnect the hot end from the wiring harness and test hot end for the proper resistance. The smaller orange wires are for the thermistor and should read ~100k at room temperature. The larger red wires are connected to the heater resistor and should read between ~4-7 Ohm. If your heater resistor reads something different send an email to the support team at