Workaround that avoids the replacement of the AC evaporator sensor from all Ford Fusions up to 2012. A problem that Ford should take care in guarantee considering the poor quality of the sensor used and because it is a recurring problem on several vehicles. Ford recommends the replacement of this sensor, to do that, the complete dashboard removal is mandatory. The service costs around U$ 600 and the sensor around U$ 20. Therefore, it is not cheap.


No tools needed.


- 1 37kOhm resistor (1/8 W);

- Electric tape;

- Stanley Knife

Step 1: Glove Box Disassembly

Disassembly of the glove box pressing it on both sides.

Step 2: Attention to the Cord!

Step 3: Connectors

Pay attention to the left connector (it may be green or blue - normally green).

Step 4: Wiring Schematics

Wires BU-BN (blue/brown) and VT-BN (violet/brown) are the wires connected to the temperature sensor (thermistor). In some cases the thermistor will open (resistance=infinite) in others it will show the problem only when moisten, it will cause the AC compressor shut down. If this is your case, the wires must be chopped off in order to guarantee the good resistance measurement. Looking the backside of the connector blue or green (wire side), the pins will be the third and fourth from left to the right on the up row. (check here: https://www.youtube.com/watch?v=imnNjh6wGo4).

Step 5: Choice of the Good Resistor

Resistor X temperature

The good resistor is shown on the chart. A 37 kOhm resistor will generate a signal equivalent to 20 Celsius and avoid the compressor to shut down. When using AC on very cold days, the evaporator may ice, in this case you have only to shut the AC off and let the ventilation working.

Step 6: Resistor Assembly

The pictures show the resistor assembled.

Step 7: Sensor Replacement

There are three good youtube videos showing the dashboard disassembly.
Shortest service time video:

Longest service time video following Ford instructions (by the book):

on a similar vehicle (Lincoln MKZ):

It works.2006 6 cylinder fusion. Pin 15 blue/gray and 13 purple/brown. 39k resistor found in old cb radio. Spiced and solder directly to above wires. 2nd from left top and 4th top wires. They are numbered on the plug but hard to see. Top left(16) was empty by the way. Very easy. Just remember to cycle ac on and off once in a while as it won't disengage on its own like its supposed to if system gets to cold and starts to freeze up. Haven't tested fully yet to verify that but that's what I've read and it makes sense. All I know is that I have ac again now and the hack works. For now that's awesome. Nothing lost.
Congrats man! If you have any photos and would like to improve this instructable, please let me know. Best. Erwin.
<p>does the wiring stay the same n u add the little ohm resister to it.or does the resister finish the electric connect</p>
<p>Did you get a response on this? i am having the same issue. Tried to splice and i didn't work, wondering about the resistor finishing the circuit</p>
It will work only if the temperature sensor (resistor/thermistor) is completely open (resistance is equal to infinite). In my case the thermistor was sending a wrong reading. I replaced the part by a new one. If this is your case, you must cut the wires going to the sensor, it means that the resistance will be only of the resistor and not the sum of the resistor and the damaged thermistor. You can also check de possibility of replacing the original part by other (it costs US15 I think) and use the technique shown in the video https://www.youtube.com/watch?v=WqLWwIFTk_k<br>. You do not have to disassemble the whole dashboard. I did that.
<p>I have a 2012 Fusion, Plug is blue, wire 13 is gray, no 14, 15 is violet.</p><p>What now.</p>
Just did this workaround on my 2012 Fusion a month ago. The two wires you want are 13 (gray/blue) &amp; 15 (violet). <br><br>Just a note: First I tried to splice the resistor across the two wires and that did not work. Second, I took a chance and actually cut the two wires and installed the resistor onto each end of the cut wires (non-connector side) and a/c works great. Just no heat now, but before winter sets in I will just remove the resistor if I do not attempt the sensor replacement myself. Good luck!
Thanks Hubcap! Yes 13 and 15 work in a 2010 Fusion. Relay check, bypass relay kick on compressor, refrigerant was charged no leaks. No blue/brown wire, should have read down a bit further. Thanks worked great.
<p>Thank<br>You for the info. I plan on putting a single throw double poll switch within<br>easy access. That should make it easy to return to normal.</p><p>Frank<br>Conko </p>
Where did you buy the resistor? I can't find that anywhere
Hi Drew, i found them at Radio Shack. Only a couple of bucks.
<p>My Radio Shack in Kansas City has 47 kOhm at .25 watt ($1.65 for a five pack) and I plan to use this size. Does anyone see a problem with this versus the 37 Kohm at 1/8 watt? From the chart it appears it will allow the compressor to work at around 60 degrees F. This is how I understand this work around to work.</p>
<p>I checked all of my local radio shacks and none have this resistor.</p>
<p>hey did any of you guys try this? And did it work</p>
<p>It works. I just had my car in the shop for a week with no answers. Bring it back home and takes me about 15 minutes to fix it.</p>
<p>All my radio shacks don't carry this resistor. Anywhere else I can get it?</p>
Call ford this is ridiculous!! This should be a recall!! Please
I have 2012 ford fusion My AC an Heat will cut on only if im hitting the gas but doesnt blow hard i will have it turned all the way up but doest blow the full power, need to know if its the blower or something else
SethS16 did you find out what was wrong? Mine is doing the exact same thing.
Did you ever find out what was wrong. Mine is doing the exact same thing.
<p>Erwin,</p><p>I have a ford fusion 2002 (European)<br>model. As your instruction I opened the glove box but I did not see any<br>connector. Any idea where I can find the wiring manual of my car and do I have<br>to follow the same steps you&rsquo;ve described? </p>
Worked like a charm. I have 2011 fusion 4 cyl SE. My wire harness was blue and pins 13 and 15 worked. Also I couldn't find a 37 kohm resistor so I used a 36 1/4 watt. No issues. Thanks so much for this instructable. Saved me paying $1000 to Ford. Entire job including soldering iron cost me only $25.
Kudos to You Craig! I'm very happy to know that the instructions were useful. If you have any photos, please send-me, I will update the info a give you the credits.<br>Regards.<br>Erwin.
Could you help me with verifying why colors my wiring would be? I have a 2011 Ford Fusion SEL, would it be the same as yours? Do you have any pics? I would like to try this on mine
Could you help me with verifying why colors my wiring would be? I have a 2011 Ford Fusion SEL, would it be the same as yours? Do you have any pics? I would like to try this on mine
I cant seem to find a 37k ohm resistor does it exist or am i miss reading ? I even googled for it and redisor charts dont show a 37k
<p>It doesn't need to be exact. 37K-38K will work just fine. Alternatively you can get two 75K Resistors and put them in parallel and that will give you ~37.5K. </p>
<p>I just tried this on my 2010 Fusion which the Ford dealership stated had a bad sensor. I'm missing the cable in the 14th slot, and as suggested I used slot numbers 13 and 15 instead. This didn't work for me. I'm using a 37.4K 1/8 W 1% MF resister. Any suggestions what I might be doing wrong? Any help will be much appreciated.</p>
Hi Mike,<br>Without the resistor, you should check the resistance on the circuit without the workaround resistor. In my car, the sensor problem happened only a few minutes after the AC was on. That means that installing a resistor in parallel with it will possibly not work if the sensor wiring is not disconnected. I will recommend that you try using a OBD2 cable in order to read the temperature measurement. It costs around U$ 30 and you can use the free ForSCAN software. That will allow you, not only to check the evaporator temperature sensor measurement, but many other parameters. As explained on the instructable, I did replaced my sensor using the technique explained here.<br>Good luck.
Mike does a 37k resistor exist i cant source one anywhere ?
My 2011 fusion does not have a wire in 3rd slot do i just go by color?
<p>What happens when the evap. sensor is bad? My 2006 Fusion was working good after we bought it in March of '15 but then when it started getting really hot it started alternating between the compressor kicking on and blowing really cold for a few seconds and the kicking off and blowing BARELY cool for a lot longer. The result being that it wouldn't cool off the rest of the car but only me because the air was blowing directly on me. The rest of the car would be hot and humid so my kids (3 &amp; 8) in the back were hot. Eventually it would cool it a little bit. I took to dealer and they couldn't find the problem so they sent it to a Ford dealer. They had the car for about 1 1/2 months between the two places because we had to take it back 5 times. Each time the problem would change to something worse. Now though it is back to the original issue and it got cold so I quit trying to take it in until it gets warm again. You can't tell there is a problem with it is cold outside. I am beyond frustrated that I now have a 4 year loan on a car that my one priority in a used car is to have working heat and AC. Also, the heat works fine.</p>
<p>Hi Guys,</p><p>i just need to know more about the affect of defected evap. temp sensor,</p><p>as i just had a recent problem with my 2012 Fusion, of AC sudden turning off (switching into hot air flow)..!</p><p>and to turn it on back, i have to restart the car engine itself.</p><p>so do you think that's the same problem of evap sensor?</p>
<p>Used this to diagnose an intermittent AC problem on my v6 2011 Ford Fusion. I located the plug. I prepped a 5K ohm resistor to fit in the slots. I waited until the AC cut out. Then, I shorted the wires with the resistor and the AC kicked back on. Pulled the resistor out and the AC turned back off. I just wanted to make sure before I spent half a day replacing the sensor. In my car the wires were Grey-Blue (2nd slot from the top left) and Violet-Brown (4th slot from the top left, the third slot was empty). I hope this helps someone.</p>
<p>Took me about 2 hours to replace the sensor and now AC works great!</p>
<p>Good! </p>
Thanks for the help! If you have some photos please send it to me and I will update de instructions with your credits. Best. Erwin.
<p>Hi Erwin,</p><p>You said you have a hybrid, what were the symptoms before you replaced the sensor? My 2010 hybrid blows 60-65 degrees, but the shop said it's got a full charge. The odd thing is the ACC power gage never goes above the second bar with the AC on Max, fan on high, etc. I know the hybrid has a variable speed compressor, I wonder if this sensor could be marginal and let it run but not at the max speed?</p>
<p>Sorry for the late answer. I&rsquo;d a busy week. My AC simply stop <br>working after a few minutes. I suppose that it is due to the broken/oxidized insulation <br>of the temperature sensor. After a few minutes working, the evaporator began to <br>put moisture on the sensor and it stopped to send the proper temperature <br>measurement. I replaced the sensor and the old one was in pretty bad shape, <br>whitened by oxidation. It is amazing that a car with only 20.000 miles (as <br>mine) would have such problem. Clearly a bad supplier choice from ford. After <br>replacing the sensor, everything is working fine, but it was such pin in the &hellip; <br>to replace it, that next time, I will make the workaround.</p>
Took the car into ford, they did an evac/recharge and replaced the service valves, of course that had nothing to do with it. They said i need a new controller for a blend door, also clearly not the issue. <br>So I went ahead and did this mod. I followed a YouTube video where the guy pulled the wires from the harness and crimped the resistor onto the wires for a cleaner install and cleaner removal eventually. <br>The result is that the AC is now ridiculously cold. I measured 18 degrees F the other morning (outside temp ~100, full sun). I used a 33k resistor. It's drawing between 4-5 bars power on the ACC gauge. <br>So, good thing, I know the evap sensor is the issue. However, I have a feeling that the sensor reading is more important than on the non-hybrid, where the only option is engaging or disengaging the compressor clutch. I'm not too sure that low 20 degree output isn't eventually going to cause issues, so now I know the sensor is the problem I'm looking for someone to replace it and fix it right. <br>
<p>Hi Greg, thanks for the feedback. In fact it is a shame that a car that is so reliable, to have a problem with such simple and cheap part. Ford should do something about it. I&rsquo;m amazed that the service guys did not figured it out at once, because is something that you easily could check using the computer tools they have. On my car, I replaced the sensor using the technique from this youtube video:</p><p>https://youtu.be/WqLWwIFTk_k</p><p>It saves a lot of work and hours, because you do not have do disassemble the steering system. The only problem is replace the dammed sensor without seeing it. But it is possible, I did it myself. Good luck.</p>
<p>Well I've been getting through the Phoenix summer with the resistor in place. AC runs way too well, the power draw kills my gas mileage since it's draining the hybrid battery so quickly, and even in 110 degrees, the evaporator would freeze up after about 30 minutes. I'd have to turn off the AC, and wait for the air to start blowing through again, then turn it back on (and hope it actually came on) and repeat as necessary. I think this is a difference in the way the hybrid works with the variable speed compressor instead of the clutch. </p><p>Now, confident that the sensor is the problem, I finally made an appointment to replace the sensor. Last night I pulled the resistor out (I had crimped it into the wires in the harness so I could remove it easily), and got ready to take the car in. But when I drove the car last night and this morning, the AC is still blowing very cold (&lt;30 degrees) even without the resistor. It never did this before the resistor hack. So I didn't take it in yet, waiting to see how the weekend goes. I know things don't fix themselves, but I'm completely at a loss to explain the behavior. </p>
<p>I think <br>that you have another problem. The evaporator temp sensor will shut off the <br>compressor only when the evaporator is way too cold, avoiding that it freezes. <br>The sensors that really control the temperature are the sensors inside the car <br>that monitor the internal temperature of the vehicle.</p>
<p>This is good info to know, especially for a temp fix (if you need to get through the week or something), but I just replaced this sensor in my sister-in-laws car, it's really not that difficult. Yes, it takes some time (about 3 hrs total), but it's worth it to know that you're not bypassing safety systems that are put into place so you don't burn out other components. </p>
<p>Hi gamonoparts, I did the same (replaced de sensor) but I am sure that this is a recurrent problem and I will have the same issue again. Next time I will put the resistor. One of the explanations why I am not very concerned about using the workaround is maybe why I live in a tropical country and the lowest temperature around here is 4 to 10 Celsius. In this case, the evaporator becoming a block of ice I think is a remote possibility. Thanks for your remark.</p>
<p>Fair enough. :) </p>
<p>I wired in the resistor and the ac now works fine. Problem is the compressor never shuts off now. Then the evaporator core freezes and I get no cold air anyway.</p>
<p>Hi Hernest, You should check other temperature sensors. The one that the replacement is being explained here, takes care only from the evaporator temperature. There are other sensors that control the car internal temperature. You should check the readings of those sensors.</p>
<p>Is this a good long term solution, and good for long drives? I'm about to make a 9 hour trip, and I don't want this to make my car explode (exaggerating, but could it make the compressor freeze or short out?) And will anything extra be required for winter when we only use the panel (not A/C)?</p>
I have A 2010 Ford Fusion sport and am not sure which wires to put the resistors on. Any help

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