HUH???
HUH???
Yes, Mr Nelson!Sam....Sam McGee.
But he doesn't really need Sam, he needs Herman.
Once you get the heater working try putting in a circulating heater. They work by warming up the coolant. That way when you go out on those cold mornings to start plowing the engine is already warm and your heater is blowing warm air. No waiting for the engine to heat up.
The other option is a s-bar heater. The work off the fuel you use to run the truck. They also have a rapid response once started. Some of the high end models can be set up on a timer. This is so the vehicle is warm if you use it the same time each day.