System Crash when Attempting to use 2nd Extruder

Hi all,
I finished building my Vertex printer fairly recently. I have been getting used to printing with the first extruder. I purchased and installed the second extruder.

If I attempt to load filament for the left extruder, the system auto-homes and then stops working. The same happens if I try to preheat the left extruder. The only way that I can recover is to press the rest button.

I checked the manual. I think that I have everything installed correctly. Any ideas?

Thanks in advance for your help.

Make sure the thermistor is connected to the middle screws on the green connector.
If this is not the problem you may want to disconnect the heater and try the load again.
It will not load because you will not have the heater but if it does not hang up this may indicate a bad heater.