Troubleshooting Repairing The Nissan Xterra Air Conditioning Repair Guide

Difficulty

Moderate

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Time Required

                          1 hour

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Troubleshooting & Repairing the Nissan Xterra Air Conditioning
6 steps

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Introduction

One possible cause of this symptom is that the Thermistor may be defective. Here is how to troubleshoot and replace the thermistor.

What you need

Step 1

              Troubleshooting & Repairing the Nissan Xterra Air Conditioning

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.

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.

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Step 2

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.

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.

Step 3

Replacing the Thermistor requires removal of the glove box.
Remove the four upper screws and the two lower screws as indicated.

Replacing the Thermistor requires removal of the glove box.

Remove the four upper screws and the two lower screws as indicated.

Step 4

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.

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.

Step 5

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.

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.

Step 6

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. You will need a small sheet metal screw to attach the mounting bracket in a hole next to the existing mounting bracket. They provided a hole for you to mount the new bracket. ( I guess they al

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. You will need a small sheet metal screw to attach the mounting bracket in a hole next to the existing mounting bracket. They provided a hole for you to mount the new bracket. ( I guess they al

To reassemble your Air Conditioning System, follow these instructions in reverse order.

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                                                                                      32 other people completed this guide.

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                    Doug Layne

Member since: 06/21/2012

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Glenn - May 22, 2013

Excellent information. My 2003 Xterra was acting up with the AC compressor kicking off and on when the vehicle got up to temperature. One mechanic told me the compressor was knocking and ready to fail. I found out that it was simply overcharged with Freon after a high pressure AC hose replacement. It has worked fine for two years now after getting the Freon right.

Doug Wacha - Aug 3, 2013

Article by Doug Layne was the answer to my 2000 Nissan Frontier Crew Cab. The Thermo Amplifier was the cause of my problem. A/C works like new. Also make sure you clean inside the unit. I have no idea how so much dirt got into the unit. Must be poor design.

Thanks Doug from another Doug

jbegleybuild - Aug 17, 2016

What was yours doing and what did you do to fix it.I just got mine 01 and the compressor is working but not cooling much.please help.

What was yours doing.my compressor is working and the garage charged it but not getting cold.they said they thouhht it was the expansion valve.what do you think

Karen Strong - Aug 6, 2013

In step 6, part of the sentence is cut off, what should it say: “They provided a hole for you to mount the new bracket. ( I guess they al”

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