2019 Defender with cab and heater, it’s damn hot inside cab with heat off, is there a fix

[Old man]

🤠

[Andystoy19]

The 2019 Cab comes with the same standard option as many of the non cab models, its called "220" air conditioning. In the days prior to any cars having AC all the cars had the 260 standard option which was 2 windows open and 60 miles per hour.

If this was a serious question the coolant flow to the heater core is controlled by a heater control valve and electric actuator. With the temperature control knob at the  "off" or far left position the valve should be fully closed and the heater core should remain cool when the temp control is rotated clockwise to increase the temperature the control valve should rotate from fully closed to fully open at maximum temperature control knob. 

If you can feel the heater core with the temperature control selector to the minimum or off position the core should be cool or cold, when you rotate the selector to maximum the heater control valve should open all the way and the core should become hot with the coolant flow from the engine. If you can locate the heater control valve and actuator you should be able to rotate the valve manually if its stuck open and you can't free it up it may need to be replaced. If it moves freely by itself but not by the electric actuator; the actuator or the selector may be at fault. The fuses are located behind the right side of the heating unit check those and check for any loose wires or connections. If you can't get to the core check air temperature or the two heater hoses to see if your heater control valve and actuator work? The heater control valve assembly appears to be at the rear of the heater, hint follow the heater hoses from the engine to the cab???

If everything checks out and its still hot you may have to revert to the "220" method until the outside air temperature gets near zero.😉

[Tug Hill]

 I happened to find the Heater Valve today while running the wiring for the new plow.  You'll need to take out 3 Torx bolts from the bottom of heater section ( where the filters are) the valve is behind that plastic filter housing.

[Old man]

Thanks for the replies, I’m going to be taking your advice and checking the system out, much appreciated.

[Andystoy19]

If you need a temporary solution once you locate the heater hoses you can place  a small clamp on one of the hoses. Make sure you don't damage the hose with too much force, this will stop the flow of coolant like the heater control valve.

Your machine should be on warranty so a trip to the dealer might be easier?🙄