How to turn your heater core off and on in the cab.

[Waterloo]

(05-24-2019 )earnies2 Wrote:  Thanks I have ordered the parts and will install when I get home I might need to do some rerouting on the hoses because of the APU but I will figure that out. Thanks for the wireing diagram and I will definitely put a fuse inline...

Just find the hose to the heater core going into the firewall, inlet side, install the valve between there (firewall) and the APU valve or T. The valve is the same size as a 1/2" NPT ball valve you will find at Home Depot, about 2.5" to 3" long. I am thinking you will probably need some hose barbs, 1/2" NPT to whatever the ID of your heater hose is, normally around 5/8" on the hose barb. you can find them in straight, 45* and 90*, Amazon, of course has the best selection. Cummins will normally carry them at a premium, and FleetPride too, if you have one near you.

Some examples...

https://amzn.to/2W2WMBN

https://amzn.to/2Wm0Koy
Here are some fantastic hose clamps, I like to use these particular ones as they compress without tearing up the hose. Worth the money in my book. Good quality.

https://amzn.to/2HzlsZz