3rd Generation Specific (1993-2002) 1993-2002 Discussion including performance modifications and Technical Support Sections.
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Fans won't shut off, ever!

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Old Jun 15, 2009 | 09:52 PM
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Uncle Hungry's Avatar
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Fans won't shut off, ever!

Well a little backround info first. It's a 93 with stock fans, just got it running with a new motor, harness, PFC, injector driver and single turbo. Its got a stock thermosensor and colder thermostat that holds a rock solid 78c at idle. I also relocated the relay box on the front crossmember to the pass. frame rail and removed the fuel pump supply from the ign to give it a true 12v. Last but not least I put the battery in the trunk.

Now for the problem, whenever the battery is on ( it's on a circuit breaker) the fans are on. It doesn't matter what the water temp, or even it the key isn't in the ign for that matter. I'm not sure if the 4 fan relays need to go with specific plugs or are they all identical because they've definitely been juggled around. I need to check again but I don't believe I screwed up the relay box wiring either. I'm mainly just curious if there is a common culprit for this situation or if I'm just gonna have to hunt down some faulty wiring somewhere.

Forgive me guys I know I did waaay to much at once but I bought the car with an empty engine bay and never worked on a rotary before in my life. So considering after all that I more or less got it to start on the first try, that ain't too bad! *pats self on back* lol. Anyway thanks on advance fellas.
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Old Jun 15, 2009 | 10:02 PM
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is your a/c on?
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Old Jun 15, 2009 | 10:06 PM
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No it's not, however when I hit the a/c switch they do spin faster like they're supposed to. After a quick glance at the schematic posted by Arghx on another thread it looks like a bad thermosensor could cause this problem by constantly grounding. But then again those relays shouldn't be able to power the fans without seeing 12v switched from the ign. Huh
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Old Jun 15, 2009 | 10:38 PM
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Double check that the sensor has not failed, or that its electrical connector has not come loose.
In order to protect the engine, Mazda has designed the circuit so that should components fail, the "fail safe" operation is for the fans to come on continuously so that the engine will be protected from overheating.
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Old Jun 15, 2009 | 11:09 PM
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mine did this bullsh*t. I ended up pulling the fuse every time I stopped the car. I've never pulled a fuse so many times.

I finally found out I had swapped the relays around in a weird pattern. Make sure they are plugged in correct order.
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Old Jun 16, 2009 | 08:10 AM
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The relays have different size mouting tabs to fit on the metal bracket. The smaller tab openings are the relays on teh bottom and the larger are the two on the top(going off memory here so forgive me if I have that reversed).
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Old Jun 16, 2009 | 03:23 PM
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Update:
I did indeed have the relays screwed up. As a matter of fact it seems you can interchange 3 of the realys however you like, they're the same. Where they must not be switched is where the relay harness plugs into the body harness. Now they work just like they're supposed to. Thanks guys!
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