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

[Waterloo]

This is an old topic... 2008 ProStar, CM-871... Notoriously ugly in regards to AC and Heat. I sorted out the pos International AC system, it finally works. Now, the other PIA issue with this archaic HVAC system, you have to crawl under the hood to get AC when it is hot, and heat when it is cold.

I'm in Michigan, it is 70+ during the day, and 40 at night. The AC in my ProStar runs continually, no way around it unless you want to go with an adrino and other such stuff that is out of my league.

Here is my solution... A ball valve with a simple on off motor on a DPDT switch. Not a selonoid, but a true shut off valve that opens and closes. Want AC, hit the switch up, the ball valve opens in 5 seconds, turn the switch off. Want HEAT, flip the switch down, wait 5 seconds and switch off. Easy peasy. No worries burning up the solenoid, because there isn't one!

I just wired it up, filled the system, tested it, and it works. Took a few hours, not a big deal, and am very happy!

I hope this helps someone.

Here are the parts I used...

The Dead Man Switch... https://amzn.to/2YyPFO3

The Ball Valve... https://amzn.to/2LMNUvr

I should be back to work next week, and we shall see how she holds up. The construction appeared solid, no clue on the board inside of the switch. It wired up easily, just follow the directions. And yes, you use all of the contacts on the underside of the switch, with two jumper cables. It was easy to do, not rocket science, just follow the included schematics.

Switch, the bright shiny one to the right...



The Ball Valve... The Blue Box...