Help on heater

[RiversideS13]

I turn on my heater 3 days ago and i cannot turn it off!!! It feels like you have your climate control 30% away from the left(cold). It is not hot air, but it is warm air. I still felt tension on the switch so i dont think the cable had fall off. My S13 A/C doesnt work, so dirving it in the day time is like hell
(black exterior + warm transmission+ heater+ California sun + Riverside desert weather)= :smash:

can someone help me?
thanks