2012 ProStar+ Heater Does Not Work While In Motion

strange I normally hear this problem with AC and not heater, have you tried playing with the "recirculate"?

 

The only thing you can do is make sure any coolant taps between the engine and cab are fully open. Other than that, the temp blend door is actuated by a little motor that is commanded from the HVAC controls so electrical diagnostics would be needed. The truck moving could be shaking loose some wiring or causing some wiring to short out. The blend door has to be cycling to go from hot to cold like that, unless there is a coolant flow problem from a partially closed tap.

 

I had exactly the same problem, but with the AC, in a 2013 Prostar. Right down to the shutting it off to make it work again. International advised that it needed to have a "recall done". They replaced a sensor, that was supposed to tell the system if it froze up. I think there may have also been an issue with a piece of the wiring harness or a plug. Sounds like there may be a similar sensor of some sort on the heat side.

 

See post #4
http://www.thetruckersreport.com/tr...rum/220500-09-prostar-heater-doesnt-work.html


What do you mean by can heater? Are you referring to the bunk heater under the mattress which is controlled by the bunk control switches? That should be turned off while you are moving. Someone could have it wired incorrectly as it's suppose to have a safety relay to shut it off while the truck is in motion. These modern trucks have servos and sensors down by the blend door that are computer operated.

From what I've read it's not something for the home mechanic. It requires the laptop and a trained technician with the proper diagnostic tools. It's a common problem with Prostars and involves some reprogramming. I would seek a dealer and not some general repair shop like a TA.

HeavyD not only is the blend door is actuated so is the heater hose on these newer trucks. I think the taps (spigots) are a thing of the past. The last one I've seen was on a 2005 model.

 

my 09 t660 has one for the cab and one for the bunk.

the 09 389 i last drove also had taps. those are the newest trucks i've driven.

i run the bunk heater when it get's below 30. knocks out the draft on the driver door going down the road.
going to buy some of that foam unsulation autozone sells to see if i can fix that door draft. when i get back home. anything under 20 degrees and that draft gets down right nippy. not to mention the rest of the cab freezing the inside space.

montana hit MINUS 20 last year. not looking forward to visiting the dakotas this year. you need the bunk heater in that kind of temps. driving down the highway. the cab alone isn't capable of doing it.