Cr10 v2 problems

I recently purchased the cr10v2 off of facebook marketplace, I have had nothing but problems. I recently had to clear out a filament jam in the hot end/ heat break.The jam was cleared out by using a hair dryer and pushing the plug out. After clearing out this jam the fans will not turn on and I receive a “Heating failed” error. If I blow hot air on the nozzle area , the system does still register the temperature change. If I leave the hot air on until about 50 - 60 the fan turns on. Not sure what it could be. Some videos I watched pointed towards it being the heater cartridge. Should I replace the cartridge or just buy a whole new hot end?