There should be a series of 22mm bungs in the water jacket on the left side of the head. If your engine has a spare, simply remove the plug and install a fan switch from a VW or Porsche and wire it in parallel with the fan switch on your receiver drier. This is the hottest part of the cooling system, so you probably want to go with a 92C switch.

https://www.pelicanparts.com/More_Info/823959481FINT.htm?pn=823-959-481-F-INT&bt=Y&fs=0&SVSVSI=2100

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Hey thanks for the info, I was talking with whunter the other day informing him I don't have a sensor in the cylinder head. And he was giving me recommendations. I have the temp sender unit in the middle of the head and two plugs on the left and right of it. I have a spare engine with the cylinder head sensor that I can transfer over if it works still. But how do you wire it parallel with the A/C Drier fan switch? I also need a new auxiliary fan because mine is shot and has no continuity and wouldn't run with a 12v lawn tractor battery attached to it