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

[Waterloo]

(05-16-2019 )Lonestar10 Wrote:  Well hookup dlogic to see if there is any codes for the blend door not working right my trucks only 2 years newer and my AC is plenty cold without having to heater core turned off But probably be even colder with it turned off.

Yep, DL is the only way to diagnose, in all but one case. I won't bore you with everything that has been done to my AC system, the only original piece of it is the evap housing under the dash/hood and the lines running back to the sleeper, where the AC has always worked.

And I am religious on keeping a fresh filter in the intake box, along with climbing up there to inspect the blend door is functioning properly, and keeping the drip tubes clear. I even dug out the Ambient Air Temp Sensor from under the radiator and moved that up to the wiper cowl. That is what made a world of difference and actually got my AC system working, to the point I had ice cold air blowing in the front of the cab. I figured that out myself with the Bodybuilder schematics after spending too much time and money to get this system working.

DL will find the faults, all but that ambient air temp sensor, that was never on the radar, but solved 90% of my HVAC issues.

I was talking to my buddy out in Phoenix yesterday, he has the same issue with his 2008 ProStar and the heater core. I sent him the links to the valve and switch.