K2 SE hot end issues.

Hello, I’m looking for some help with me K2SE.

I’ve had the printer since April and have been printing without issue since then. However, whilst changing the nozzle this week I managed to break the wires on the hot end. I’ve replaced the hot end unit but it’s not working. I’ve tried 2 different hot ends, put high temp grease on the heating elements/nozzles, but still getting nothing. I even tried a factory reset but now it won’t even get through the self check as the nozzle won’t heat up.

Any help or advice would be so appreciated. I’m pulling my hair out.