* Blend Door Actuator: This small motor controls the mix of hot and cold air. If it's stuck in the "hot" position, you'll only get hot air. This is the most common culprit. It might be failing mechanically or electrically (faulty motor).
* Blend Door Cable (if applicable): Some models use cables instead of an actuator. If the cable is broken, frayed, or stuck, it could prevent the blend door from moving correctly.
* Vacuum Lines: The HVAC system might use vacuum lines to control the blend door. A leak in these lines will disrupt the operation and could result in only hot air.
* Control Panel/Module: While less likely, a faulty control panel or HVAC control module can send incorrect signals, causing the system to always deliver hot air.
* Stuck Blend Door: The blend door itself could be physically jammed or broken, preventing it from moving from the hot air position. This often requires more extensive disassembly to fix.
* Refrigerant Issues (Less Likely): While unusual for *always* hot air, a complete lack of refrigerant in the AC system could prevent it from cooling, resulting in only hot air being available. However, you'd typically expect some variation depending on whether the heater was engaged.
Troubleshooting Steps:
1. Check the obvious: Ensure the climate control settings are actually set to cool and the AC is turned on. Sometimes a simple user error is the cause.
2. Listen for actuator noises: When you change the temperature setting, listen near the HVAC control panel/blower motor for a clicking or whirring sound from the blend door actuator. If you hear nothing, it's likely faulty.
3. Inspect vacuum lines (if applicable): Visually inspect the vacuum lines for any cracks, breaks, or disconnections.
4. Test the blend door (advanced): This requires removing parts of the dashboard to access the blend door. Try manually moving the blend door to see if it's stuck. *This is generally not recommended unless you have experience with automotive repair.*
Recommendation: Since the blend door actuator is the most common cause, it's a good place to start. You can purchase a replacement actuator relatively inexpensively and install it yourself (if you're mechanically inclined and have the proper tools), or have a mechanic diagnose and repair the issue. A proper diagnosis often requires specialized tools and experience to pinpoint the problem accurately.
