Heat wont turn off... HELP IM OVER HEATING

just wondering if anyone has any idea as to why my heat wont turn off. if i switch it to cold it just stays on heat, and if i put it on heat it stays on heat. the fan works in low/medium/high/defrost etc. Thanks in advance!!

What year truck? It sounds like it could be the blend door.

You could always bypass the heater core (two hoses at the firewall in engine compartment) until you get it fixed right. You'll need heat in BC.

Check that the cable is still hooked up to the heater valve and it shuts the valve off.

Thanks guys, another member already helped me narrow it down to the temperature selector switch. Now I just have to find one...