I know it's nearly 30 degrees C here in the Okanagan but I'm trying to install a espar hydronic 5 series(24 volt) in a BJ74. Iv'e got the heater mounted including fuel lines,exhaust,plumbing(only took me 3 days, and why am I doing this) and most of the wiring.Everything works fine,i'm cooking myself out of the cab but I can't figure out how to wire the cab fan motor so it goes on when the the espar heater reaches the desired temperature.Iv'e located the wire from the espar control unit that controls the heater blower and ran it through a relay and am trying to hook it up to the blower in the cab.Does anyone have a wiring diagram for the heater blower,birfields download manuals aren't working.Has anyone installed a espar or webasto heater in a BJ74.I usually work up north and have no use for ac or even in the Okanagan for that matter, much rather have a diesel heater for the rest of year.