My 2003 Nissan Xterra has recently had a few things go wrong up until now I knew how to fix. Now I have only HOT air coming out of the interior vents. It doesn’t matter what I do. I turn the knob to cool and turn the AC on and no cold air. I know that cool air isn’t being introduced to mix with the engine air. What are some possible solutions and areas to look at.
You most likely have a leak in the A/C system and it is low on refrigerant. Can you see or hear if the compressor is engaging when the A/C is on? This is something that is best left to a shop to handle. One thing to avoid is using the A/C quick fixes that auto parts stores sell, the “leak stop” that is added to these products can create even more problems.
Sounds like a blend door issue. The hvac control can be manual or you may have a more complicated auto climate control. That is the front end. All cars have a blend door that varies the mix of cold/hot air. This door usually has a small electric stepper motor. Sometimes it is vacuum operated depending on car age.
can you see if the blend door is driving. Here are the drawings.
Check for diagnostic trouble codes and make sure all the fuses are ok. If it isn’t discovered by that route, and you don’t see/hear anything unusual under the dash happening when you adjust the hvac controls, you’ll probably need a shop for this one. If what you want to do is simply prevent the heat from coming out, you could bypass the heater core of course. But then you’d have no heat in the passenger compartment at all.