Jeep TJ HVAC Blows On Defrost Only Fix

How to fix your jeep wrangler tj hvac system if the fan speed works but only blows out of the defrost vents on the top of the dash and the A/C heater vacuum switch does not work and won't switch between the different modes like recirculate, air conditioning, face or feet setting. The HVAC mode selector switch on a Jeep TJ, often referred to as the A/C heater vacuum switch (for 1999-2004 models) or the Mode Switch (for 2005 models), controls the direction of airflow through the vehicle's vents. This switch is located on the far right of the HVAC control panel and is responsible for changing the airflow from floor, to dash, to defrost, and other settings. If the switch is malfunctioning, the airflow may not change correctly or the knob may spin freely, indicating a need for replacement. The switch operates using vacuum pressure, and if it loses this pressure or becomes damaged, it can cause the airflow to be stuck or erratic. The switch is connected to a three-pin connector on the back of the HVAC control, with specific wires designated for different functions: a black wire for ground, a dark green wire for the fan speed control, and a light green wire that grounds to the Powertrain Control Module (PCM) when the AC or defrost is selected. The light green wire is a key signal wire for the AC compressor engagement. For troubleshooting, if the blower fan runs continuously, it may be due to the B and C wires to the mode switch being in constant contact, often caused by a melted or improperly insulated connector. Replacing the switch is a common fix, and a replacement part is available from Mopar or aftermarket suppliers, typically costing around $20-$30. The replacement process involves removing the plastic faceplate covering the HVAC controls by popping off clips located below the windshield, which allows access to the switch for removal and installation. Don’t forget to LIKE, SUBSCRIBE, and hit the bell for more How to videos, restorations, and mods on KyleSVT! Drop a comment Let’s talk! My discord:   / discord   Need parts? I got mine from https://www.amazon.com/shop/kylesvt Follow me on X for updates: @Kyle_SVT Join my channel to show extra support and get access to perks:    / @kylesvt   My Amazon Store Page: https://www.amazon.com/shop/kylesvt Sponsor Links Tekton Tools: https://www.tekton.com/my-lists/kylesvt Baja Designs: https://www.bajadesigns.com/ 10% Discount Code - KyleSVT10 Rinse Kit: https://bit.ly/3Y5JZLl #jeeptj #hvac #fix