Tried to Upgrade Mini V1 firmware now Bed Heat problems

Hi, Im new to the group so please bare with me. My Mini was working fine running stock firmware on Cura 21.04
I wanted to use a more modern version of Lulzbot cura (I have 3.6.3) but could not get it to work. I decided to update the Firmware. after updating and re setting my e-Steps I tried to do a test print. machine sounded very different and wouldnt stop at the limit switches. I downgraded back to my original Firmware and now cura 3.6.3 no longer recognizes my machine and Cura 21.04 only gives me the message "Minitemp triggered, system stopped.
Heater ID bed
Printer Halted, Kill () called.

I believe this is telling me that the machine cannot read the temp of the bed so it is not continuing. Is there a way to check the bed Thermistor to see if it is bad (Ohm Reading?)
Anything else I should be checking?

Thanks in advance