Prostar heating issues

Been through it, multiple shops, thousands of dollars over four years, none of the mechanics fixed mine. I did. Good luck.

 

Just for kicks...the shop repaired your A/C and claim it has nothing to do with the heater. You should call the shop and ask the Manager to review your claim. If he insist on not being liable, go up the chain of command to the V.P. or even the CEO with your complaint. Somebody did something wrong and now they act like its your fault.

 

There is a coolant control valve on top of your engine (passenger side). If the hoses are cold, it's likely the valve is closed. Open it.

Top off coolant. Use a sharpie to mark coolant level.
Start engine and idle to operating temperature. If coolant level drops, top it off.

After that valve is opened and coolant is circulating, you may have to bleed air from the heater core. If your cooling system has a bleeder valve, it will be at the highest point on the engine, cooling system or heater.

 

There are no coolant control valves on a Prostar. Some do have shut off taps if it has an aux heater. Hot coolant circulates through the heater core the same as it does though the engine because of the engine water pump. The temp blend door just direct air flow either through it or around it. Once you unplug the HVAC controls and plug it back it, it will automatically calibrate at key on. It is actually plug and play in that regard. You are probably right in that the plastic drive collar is broken on the actuator and that is why the heat isn't working.
Check out this post, it shows a diagram of your heater and where the actuators are located. Blend door is #4.

 

Well... I've seen the engines of exactly two Prostars: 2011 & 2012 model years. Both had MaxxForce engines. Both had bunk heaters. Both were plumbed for tanker in-transit heat. Both had coolant control/shutoff valves. How do you explain this?

 

That's how. Trust me, bud. I'm pretty sure I have seen more Prostars than you!.