Its a '55 series 0ne. I do have a flow adjuster that controls the heat. I pressure tested it by connecting to the house water main, so that should be ok. But I'm having trouble with the fan. I cant get a switch for it to control the air flow. Comes out like a rocket. Looking at another thread it may be that its still 6v? That's why it was disconnected. How can I tell?
I may have to get a 12v to 6v reducer. One thing after another.
If the truck was original when you bought it it'll more than likey still be 6v,there are 12v motors available.