constant 12v output on hotend connectors

I have an all in one ramps board on my Hictop printer. I have had this printer for just over a year with many issues that I have been able to correct by a quick google search but this recent one is driving me crazy. After switching filament I have been stuck in a loop of calibration which resulted in 2 blocked nozzles. On the third try I finally got it to extrude and it printed fine. The next print I couldn't get a stable temp and on closer inspection the thermister and heater had somehow fell out of the heat block. No idea how or when this happened because the print prior was a successful vase mode temp calibration. It was a tight fit to put them back in the block and I added some thermal paste around the thermister. When I tried starting the print again the temperature was not only unstable but went up to 274 degrees and knocked itself off. the power supply wouldn't turn on until the nozzle cooled down below 50. Upon turning on, the heat block had a mind of its own and immediately started heating up ignoring the cool down command or manual control. after tripple checking all my wiring was correct I though the thermister was the problem after reading they often go bad, so disconnected it to get min temp error and when I turned the printer on I touched the heat block and felt it heating up.

I have had problems with the terminal blocks in the past, having them completely burn out about 6 months ago so I soldered on some higher rated terminal blocks so I cant imagine it would be a software issue. Does anyone know of potential issues that could cause this always on state on the ramps board?

sounds like a short circuit mosfet

Ok so you are right. The e0 mosfet is showing different readings on my multi-meter than the e1 mosfet. Only problem now is finding a replacement. I cant seem to find the exact model. they have printed on them IRFZ44N P520P XHT8. Dont know what that means but the closet thing I found was IRFZ44N P519D P9PO. Im pretty sure the board will still function without a mosfet for e1 so I will move it over to e0 and leave it empty unless that is not advisable. I have not got a clue what the spec of the mosfet is and I don't feel confident selecting a replacement unless it was the exact model. Any pointers here would also be appreciated.

You can run the ramps without the E1 FET fitted,however, if you have a print cooling fan connected to the E1 connector then the fan will not work.
A better replacement for the IRFZ44N would be a IRLB3034PBF

alright thanks for the help. I do not have a fan on e1 so i will shuffle the mosfet over for now and order a few IRLB3034PBF for a backup.