2002 Jeep Wrangler 4.0 tj I have changed blower motor, resistor, hvac controls and checked fuses. Still no heat or air doesn’t blow at all. when on can hear the compressor kicking on an off. Don’t kno what else it would be I’d appreciate any advice on what it could be?thanks
HVAC system isn't working
- Thread starter Jeeper02
- Start date
1. Check the blend door actuator: The blend door is responsible for directing the airflow between the heater core and the A/C evaporator. If the actuator is faulty, it may not be properly opening or closing the door. You can try locating the actuator and manually moving the door to see if that changes the airflow.
2. Inspect the HVAC control cables: Sometimes, the control cables that connect your HVAC controls to various components can become loose or disconnected. Inspect these cables for any signs of damage or disconnection and ensure they are properly connected.
3. Check the vacuum lines: TJ HVAC systems in utilize vacuum lines to control airflow. Inspect these lines to ensure there are no leaks or blockages. This may require a smoke test as many times vacuum leaks can be pinhole sized and thus hard to track down.
4. Examine the A/C compressor: Although you mentioned that the compressor is kicking on and off, it's still worth checking the pressure in the AC system. If the pressure is too low, it can cause the system to malfunction.
5. Consider a professional diagnosis
You need to check the connectors at the blower motor, the resistor and on the back of the control panel. See if any of the connectors are burnt or if there is a spread terminal.
First we need to narrow the concern, so we can start a diagnosis. You said no heat, no air, doesn’t blow at all. That is 3 concerns. Let’s start with the blower as you cannot tell is you have heat or air if it doesn’t come out of the vents.
Check the blower motor relay. Pull the relay and check for battery voltage at pin 4 (Jeep diagram) pin 30 (relay diagram) you should have 12volts at all time (key on, key off) if not check fuse 1 if it does have power take a wire and jump pin 30 to 87 see if the blower works if it does. Try swapping the relay with another one. If that fixes it replace relay if not need to check the relay control circuit. Check for power and ground at terminals 85 and 86 one should have power with the key on and one should be grounded at all times. You can put a test light between the two to check both at the same time.
Check the blower motor relay. Pull the relay and check for battery voltage at pin 4 (Jeep diagram) pin 30 (relay diagram) you should have 12volts at all time (key on, key off) if not check fuse 1 if it does have power take a wire and jump pin 30 to 87 see if the blower works if it does. Try swapping the relay with another one. If that fixes it replace relay if not need to check the relay control circuit. Check for power and ground at terminals 85 and 86 one should have power with the key on and one should be grounded at all times. You can put a test light between the two to check both at the same time.
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