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Discussion Starter · #1 ·
Hey guys, pretty new to here and I couldn't find this in any search. I saw where the gen 1 have this issue but not so much the gen 2. My 6's engine cooling fan is running as soon as I start the car, it does not matter if the engine is hot or cold or running for that matter. I can go in and put it in the "on" position without starting the car and the fan will immediately come on. I've tried replacing the relay in the engine compartment fuse box and that did not help.

Does anyone know what else could be the issue? I do not think these cars have a fan control unit like the gen 1 and v6 model. So any ideas? Thanks in advance.
 

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Are you talking about the radiator fans or A/C condenser fan? The condenser fan will always be running but the radiator fans are only suppose to kick on when the thermostat reaches a certain temp. Unless any one chimes in with the contrary, I'd check the thermostat first. Unplug the thermostat and see what it does.
 

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Discussion Starter · #4 ·

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Are you throwing any codes by chance? CEL lights? This is the thread I was referring to when I made the above suggestion:

http://forum.mazda6club.com/2-3l-i-4/254985-thermostat-location-coolant-questions.html

Assuming you replaced the correct fuse, this is the only thing I can think of that's causing your fans to kick on if it's a thermostat issue.

If it's a Sensor issue:

https://www.ifixit.com/Answers/View...+as+to+where+the+Coolant+Thermostat+Sensor+is

Here is a walk through replacement.

I guess what you need to know is if you're throwing any codes and what codes are being thrown.
 

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Discussion Starter · #6 ·
Are you throwing any codes by chance? CEL lights? This is the thread I was referring to when I made the above suggestion:

http://forum.mazda6club.com/2-3l-i-4/254985-thermostat-location-coolant-questions.html

Assuming you replaced the correct fuse, this is the only thing I can think of that's causing your fans to kick on if it's a thermostat issue.

If it's a Sensor issue:

https://www.ifixit.com/Answers/View...+as+to+where+the+Coolant+Thermostat+Sensor+is

Here is a walk through replacement.

I guess what you need to know is if you're throwing any codes and what codes are being thrown.
Thanks, I already bought the ECT sensor I just have not replaced it yet. I had autozone check the codes and they said there were no codes.

The relay that I replaces was in the fuse box in the engine compartment, and according to the mazda parts guy it was the correct fuse. I tested it by removing the relay and turning the car in the "on" position and the fan did not come on. It did however come on when I put the relay back in and put the car in the "on" position, or started the car.

I'll replace the ECT sensor and report back the results, I would however thing a bad sensor would throw an CEL.

I do not think it is the thermostat as usually when a thermostat is bad, temperatures will rise on the gauge and then go back down when driving. This doesn't happen the temp gauge stays steady at just under half way.
 

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Sounds like you've done all the necessary troubleshooting. If you replace the sensor and it's still happening I'm going to have to tap out of this one lol. The tech at mazda or parts guy didn't have an idea?
 

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Discussion Starter · #8 ·
Sounds like you've done all the necessary troubleshooting. If you replace the sensor and it's still happening I'm going to have to tap out of this one lol. The tech at mazda or parts guy didn't have an idea?
Well I did not change the sensor but I did unplug it last night and start the car, no change except now I have a CEL. So I'm guessing that that is not it, I'm going to call mazda again and see what they say.
 

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Discussion Starter · #10 ·
Ok I finally got it fixed. After talking to a couple mechanics at mazda and a few others at other places. The fan itself was at fault, basically this problem rarely happens with the 2nd get i, and the control module for the fan is built into the cooling fan assembly itself. So I had to replace the entire fan unit, which fixed the problem. Luckily I found a junkyard that had a used one for $150 instead of the 500+ that mazda wants for one.
 

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Hello all. I have the same issue as the original poster. Just bought a 2012 Mazda 6. 87000 miles. Fan kicks in with only the key in acc position. Anyone else has or had that problem? Switch the relays as well...no luck. If so please let me know.
 

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Hello all. I have the same issue as the original poster. Just bought a 2012 Mazda 6. 87000 miles. Fan kicks in with only the key in acc position. Anyone else has or had that problem? Switch the relays as well...no luck. If so please let me know.
The previous post says that replacing the fan assembly fixed the problem.
 

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So for those who run into this problem there is a relatively easy fix. No need to replace the entire assembly, at least on my 2012 2.5. Autozone has a fan control module for around $85 with lifetime warranty.. The access is easy, the only hard thing for me was to unplug those 3 connectors. I removed the airbox cover only to replace the air filter which was original and quite dirty. As I said earlier I checked the relay first to make sure it is not dead. It wasn't the sensor since there were no codes. So it must have been the fan control module, and it was. Again no need to pull and replace the entire fan assembly.
Hopefully this helps someone with 2nd gen Mazda 6 I. I am attaching a few pics for your reference.
Automotive tire Hood Motor vehicle Vehicle Bumper
Hood Automotive tire Motor vehicle Bumper Bicycle part
Motor vehicle Automotive tire Hood Bumper Automotive exterior
 

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I've replaced the fans, the fan control module, the ect sensor, the radiator, and the thermostat. The radiator fan still runs full blast constantly. Not the ac fan, the regular engine fan. I'm actually stuck.
 

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Check your fan relay, it may be bad and stuck in the on position. The fan relay is located in the engine bay fuse block. The fan, blower, and headlamp relays are the same (L110-67-730) so you can swap the headlamp relay, for example, with the fan relay and see if there is a difference. If the fans stop running when you put the relay from the headlamp in the slot for the fan, then you know for sure that you have a bad relay. Replace it.

Below, I'm pointing to the fan relay.

 

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While you're at it check the coil contacts on the socket for said relay. When the fan shouldn't be on there should not be voltage on them. If there is, start tracing backward until you figure out why.
 

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I sincerely appreciate y'all's input! I did swap the relays. Same issue. I'm gonna backprobe the circuit. Although, I did install an aftermarket fcm. It was inexpensive. I have a feeling that may be the issue.
 

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I sincerely appreciate y'all's input! I did swap the relays. Same issue. I'm gonna backprobe the circuit. Although, I did install an aftermarket fcm. It was inexpensive. I have a feeling that may be the issue.
A new, but defective, fan control module is a distinct possibility.
 
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