Is it just blowing cold air, or is it just not functioning period? Mine would only blow cold air but all my functions worked like floor to overhead and speed. I was just not getting it to produce any heat.
I actually tore into it last night and got it to blow heat once again. My problem was the switch that turns it from hot to cold, I believe it's called the blend door actuator. All I did was pulled the interior pieces off the rear passenger cargo area out. Once I did that I located the one that controls the hot/cold which was the one located in the center of the unit. They should have an aluminum/metal round piece sticking out of them which i believe is the switch. Mine would not turn when I switched from hot to cold or visa versa. I tried to use a large flathead to manually turn it with no luck. So I just disconnected the harness and removed the unit. It's held on by 3 hex head bolt, then you can just pull it straight off. Once removed, you will see where it's supposed to turn with the switch, I just turned it using my finger and it started blowing hot air
I ended up opening the unit and turning it manually to realign with with the new position of the switch. I haven't looked into what a new actuator will run but, I'm just happy to have heat back there again and so are my kids
lol. Hope this helped.