09 Prostar heater doesnt work

Need more info. air come out the vent ? if cold the water valves may be closed.

 

where are you where you need a heater/defroster? I want to drive to that area

 

Hi, if you have blower air coming out of dash vents, what i normally find is an actuator motor failure for changeover. The motor is located on the passenger
side. remove upper fuse cover and then lower cover over hvac assembly , you may have to remove lower door sill plate and r/s kick panel for access ,
there are two motors on the left side of the unit , the one on the outside controlls the blend air door the one close to the firewall is the one you need to check. What we normally find is the drive lug on the motor has cracked allowing it to spin. (motor is attached with 2 torx screws) The motor can be a little tricky to line up when you replace but if you feel the flats on the door itself you can turn the key on and allow the motor to cycle ( it will turn 360 deg. both ways) and then figure alignment. if motor dose not cycle you may have a controller or wiring problem (pretty rare)
hope this helps.

 

Could be a temp blend door or actuator like DD mentioned or the unit could have coolant shut off taps to prevent the heater core from getting any engine heat through it. Open your hood and look for some taps around the turbo and make sure they are open.

 

I have a 2018 international 4300. I have the same issue no heat in the cab. but can't find any threads for my specific truck (truck came with no manual) Would there be valves under the hood for this truck? Had the truck built from Rody's truck center in Florida have ran into more trouble than you can shake a stick at with this truck.
Thanks

 

Heater hoses go into the firewall at the right hand side. Follow the hoses to the engine. It may or may not have taps, but just following the lines is sometime the only way to see. If no taps, with the engine warm, touch the heater hoses going into the cab. If they are hot, you know it isn't a tap or coolant problem and you might have a temp blend door problem.