2011 kw t660 heater not working?

[jimeneztrans84]

When I bought my truck in January the heater was working and in summer time I shut off the coolant valves that go to heater because I wasn't going to be using my heater. Well a couple days ago I open up the valves to turn on my heater and now it's not blowing hot only cold. Any thoughts?

[Nilao]

Heater core plugged up maybe? Do both lines get hot? Perhaps the blend door is stuck? Just a couple thoughts.

[jimeneztrans84]

I think the temp knob on the cab is not working because when I turn it to hot on ac it doesn't change temp. I tried my sleeper heater and that works good blowing hot. So I'm thinking the knob on cab doesn't work. I'm going to double check my fuses.

[jti2015]

There's a water control valve located in the engine compartment near the A/C box. Check out to see if it's operating. The valve is electric operated.

[joed2323]

(11-18-2016 )jti2015 Wrote:  There's a wvater control valve located in the engine compartment near the A/C box. Check out to see if it's operating. The valve is electric operated.

Should be located on the p/s firewall.

You could possibly pinch one of the coolant hoses off going into the heater core/coolant valve, see what that does. Or even tap the electronic coolant valve that was stated previous.

Stupid electronics.

I remember the old days when this was operated by a cable, and it use to cease up, and you had to lube up the mechanism to allow easy travel...