Troubleshooting & Repairing the Nissan Xterra Air Conditioning The 2000 Xterra's Air Conditioning is sometimes cool but may not work other times. The Air Conditioning System will get cold when the Compressor Clutch is engaged but the clutch quickly quits and just blows semi cool to warm air. One possible cause of this symptom is that the Thermistor may be defective. Here is how to troubleshoot and replace the thermistor. The Thermistor connector is located below the glove box. You can see the white connector hanging out from under the dash. The purpose of the Thermistor is to keep the Evaporator from freezing. It does this by measuring the temperature and turning off the Compressor when the Evaporator gets below approx. 40 degrees F allowing the Evaporator to defrost. Locate your Air Conditioning Compressor. The clutch is the center area. If the clutch is engaged the center area will be turning. It will be turned off by the Thermistor to prevent the Evaporator from Freezing.

Here are the tools that you'll need to complete this guide. Test the thermistor by turning the Engine ON and the Air Conditioner ON. Using a Voltmeter (set to DC Volts), the Green/Orange wire will have battery voltage (around 13.5vdc) from fuse #29 in the under hood fuse box. The Blue wire will have battery ground from the AC control assembly. The most important wire is the Blue/Black wire. The Voltmeter will show less than .5 volts with the thermistor on (temperature above 45 degrees F). It will show a nominal 4-5 volts with the thermistor off (temperature below 40 degrees F). During inital operation, the temperature at the evaporator will be above 45 degrees and the Voltmeter should read less than .5 volts. When the temperature of the evaporator is below 40 degrees F, the Voltmeter will read 4-5 volts which turns the Air Conditioner Compressor OFF. This keeps the Evaporator from freezing. If your Thermistor is reading 4-5 volts when you first turn the AC on then your Thermistor is defective and needs to be replaced.

Replacing the Thermistor requires removal of the glove box. Remove the four upper screws and the two lower screws as indicated. Using a philips screwdriver, remove three screws. (as indicated by the orange circles) Using a 10mm socket, remove four bolts (as indicated by the blue squares) The two on the right are easy to see but the two on the left are difficult to see and are behind structure. Here's were it can get tricky. Of course the correct way to replace this is to completely evacuate the system and remove the evaporator but with a little ingenuity you can have it replaced in 10 minutes. Open the evaporate shell by splitting the halves. I used a spring clamp, backwards, to help me hold the halves open. Using a long pair of needle nose pliers, gently work the Thermistor out of the evaporate fins. I purchased a new Thermistor for $52 at the dealership. Install the new thermistor by using the Long Needle Nose Pliers to insert into the evaporator fins.

Removing the connector from the bracket was difficult and I broke the bracket. I was happy to see that a new a mounting bracket came with the new thermistor. ac unit for 1500 sq ft houseYou will need a small sheet metal screw to attach the mounting bracket in a hole next to the existing mounting bracket. heat pump ac window unitsThey provided a hole for you to mount the new bracket. pop up ac unit for sale( I guess they al To reassemble your Air Conditioning System, follow these instructions in reverse order. 12 other people completed this guide. Past 24 Hours: 57 Past 7 Days: 521 Past 30 Days: 2,605This time of year, especially when it gets cold outside in the evenings, we get many calls from homeowners concerned that there is cold air blowing out of the duct registers in their home when their heat is running.

We wanted to address this, as many times homeowners think this is an issue with their heating and cooling system, but if they have a heat pump, it's actually typically a very normal process. Don't know if you have a heat pump? Check out this article, on how to tell if your unit is a heat pump or air conditioner. In the summer, a heat pump picks up the heat in your home and dumps it outside. In the winter, your heat pump picks up heat from the outside and dumps it into your home (yes, even when it's cold outside). Now, that may be hard to grasp, but this is the way it works. In the summer, your indoor coil is cold (and pulls humidity out of the air, and comes in the form of water) which is drained from that PVC pipe located on your roof, or side of your house. In the winter, that same humidity is pulled out of the air, but it comes in a form of frost on the outdoor coil (condenser). If you see frost on the outdoor coil, it is natural to the process and it is not a sign of any kind of malfunction- the reason the coil is cold falls back to the second law of thermodynamics- which states that energy always moves from areas of higher concentration to areas of lower concentration.

As the frost builds up on the outdoor coil, it could potentially inhibit the ability for air to flow across that coil. Once the frost builds up, your heat pump automatically goes through what we call, a defrost cycle to keep allowing the air to flow across the coil freely (which is a necessary function of your system). You may have noticed a loud sound right before cold air blows out through the vents in your home. The sound you hear is the reversing valve switching your unit over to cooling mode. Frost on the outside coil is condensation that forms up on the coil in the form of frost. When a heat pump begins the defrost cycle, the outdoor fan shuts off and the system switches over to cooling mode. The reason for this, is that in the cooling mode, the outdoor coil actually becomes hot. This is because hot refrigerant circulates through the outdoor coil, which in turn melts the frost. The reason the fan shuts off during this process is so the system doesn't pull the cold air from the outside across the coil while the hot refrigerant circulates.