Quick Fix (workaround) Ford Fusion AC Evap. Sensor

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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.

Tools:

No tools needed.

Material:

- 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):

Workaround
on a similar vehicle (Lincoln MKZ):

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134 Discussions

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bob1781

4 months ago

I spoke to soon. I put the resistor in to fix the ac problem and read a post that someone lost the heater after doing so. I put a DPDT switch in so I could run ac thru the resistor in summer and flip the switch to run thru the original sensor for the winter. The ac works fine, but not that its getting colder I find the heater is not working regardless of switch position. Any ideas?? Thanks Bob

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bob1781

4 months ago on Step 6

Thanks for all the info on the ac evaporator sensor problem. I installed a 37k ohm resistor between pins 13 and 14. I cut the wires going to these pins and installed it. My ac is now putting out 57 degrees and 43 on ac max. But heater blows ouside air temp, so I installed a DPDT switch so that in winter it will be hooked to evaporator senser and flip switch in summer to read through resistor. Switch is installed in glove box. Works perfect. $3 instead of $900 to Ford!

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bob1781

Question 4 months ago on Step 6

my 2010 ford fusion does not have a wire in third pin from top left. Everyone says to putthe resistor between the wires on 3rd and 4th pin from the top left??

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dsabastian

Question 7 months ago on Step 7

Which wires would it be for a 2008 Ford fusion

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KentonL1

Question 7 months ago

I am working on 2011 fusion with 3.0 auto A/C and put a 37 kOhm resistor in line at plug and a/c worked good for 30 minutes, turned car off and restart, no problem. After shutting off for 30 minutes then restart a/c would not engage compressor also radiator cooling fan not turning but did earlier when a/c was engaged only. Whats my issue, I need help

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KentonL1

Question 7 months ago on Introduction

Does the heated front left seat shutting off after a few seconds have any to do with compressor not turning on?

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sbac05151122

Question 8 months ago

OK I did the bypass and the compressor is turning but blowing hot air - what could be my other problem? It has gas in the system.

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sbac05151122

Question 8 months ago on Step 1

I have a 2010 Mercury Milan. I realize they are basically the same car, however, when I attempted this quick fix the wires are not color-coded the same. I jumped the 3rd and fourth wires but it still will not work. Are the wires I need to jump different in a Milan?

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Griffci

Question 8 months ago on Step 1

I did the resistor trick and it worked great for 5 minutes then stopped. Has anyone done this on a car with automatic climate control? I think thats the problem.

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FJCSR

2 years ago

I have a 2012 Fusion, Plug is blue, wire 13 is gray, no 14, 15 is violet.

What now.

8 replies
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Hubcap6964FJCSR

Reply 2 years ago

Just did this workaround on my 2012 Fusion a month ago. The two wires you want are 13 (gray/blue) & 15 (violet).

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!

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Mr.`Hubcap6964

Reply 8 months ago

what do you mean the " non connector side" I have a 2012 Fusion also and i tried to splice and solder the resistor onto #13 and 15 wires and didn't work neither . I am just not clear by what you mean when you said you cut the wires on the non connector side, please explain.
Thanks

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CoryW42Mr.`

Reply 8 months ago

I think he means the end of the wires coming from the harness and not coming out of the connector that you snap in. I’ve tried both ways on my 2012 with blue plug and can’t get the compressor to click on. To make it even worse my Honda AC quit working today.

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Mr.`CoryW42

Reply 8 months ago

damn that sucks !! I feel you though !

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FJCSRHubcap6964

Reply 10 months ago

I did it with a switch in the circuit, so I can switch it in or out. Mine works even the heat part.

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DanielB767Hubcap6964

Reply 1 year ago

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.

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FJCSRHubcap6964

Reply 2 years ago

Thank
You for the info. I plan on putting a single throw double poll switch within
easy access. That should make it easy to return to normal.

Frank
Conko

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Mr.`

Question 8 months ago

hi i have a 2012 Ford Fusion and as you can see the 3rd wire is not there ?? where do i solder the resistor then?

image.jpg
1 answer
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Mr.`Mr.`

Answer 8 months ago

by the way , I tried soldering the resistor to #13 & # 15 but it didn't work . I hear the Ac condenser start for a few seconds and then stops.