cooling issues-fans are confusing me!!! plz help

Ok, so I have a 94 miata and have been having cooling problems this summer.

Problem is when I have the a/c on the car will overheat at stops and/or while even going as slow as 40mph. Good thing I drive all highway to work everyday!

no fans come on with the a/c off and the car is overheating. When I turn on the a/c regardless if the car is cold or overheating the drivers side fan comes on(which is the cooling fan correct?). With the a/c on the drivers side fan come on and off with the compressor. I would think that the condenser fan should come on right?

So I did the jumper trick with the diagnostic jumer box and with the key on the drivers side fan comes on. Not the passenger side.

So I think I have a couple issues here.

1. The cooling fan(drivers side right?) doesn't come on when the car overheats but when the a/c is on.

2. the condenser fan(passengers side) should come on with the a/c clutch. Not the drivers side.

I know the condenser fan workings because I took it out and hooked it up to 12v power and the motor came on. I took the thermo switch off and grounded it with no luck. I also grounded the blue/white ground wire coming out of the a/c fan relay and not luck there. It is supposed to run to the pcm and the pcm should ground it to turn on the a/c fan.

I tried to type this up as best I can. If something doesn't make sense plz let me know.

Thanks for all suggestions.

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Originally Posted by Strider

Ok, so I have a 94 miata and have been having cooling problems this summer.

Problem is when I have the a/c on the car will overheat at stops and/or while even going as slow as 40mph. Good thing I drive all highway to work everyday!

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Quote:

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Originally Posted by Strider

no fans come on with the a/c off and the car is overheating. When I turn on the a/c regardless if the car is cold or overheating the drivers side fan comes on(which is the cooling fan correct?).

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The driver's side fan is indeed the cooling fan. The PCM should start the cooling fan at about 205*F. There is a coolant temperature sensor above the bell housing, at the back of the engine.

Quote:

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Originally Posted by Strider

With the a/c on the drivers side fan come on and off with the compressor. I would think that the condenser fan should come on right?

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Yes, both fans should run with the compressor on.

Quote:

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Originally Posted by Strider

So I did the jumper trick with the diagnostic jumper box and with the key on the drivers side fan comes on. Not the passenger side.

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Jumper in TEN and GND, both fans should run when the key is on and the accelerator pedal is depressed. When I am working by myself, I use a shortened broom stick jammed between the pedal and the seat to hold the pedal down.

Quote:

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Originally Posted by Strider

So I think I have a couple issues here.

1. The cooling fan(drivers side right?) doesn't come on when the car overheats but when the a/c is on.

2. the condenser fan(passengers side) should come on with the a/c clutch. Not the drivers side.

I know the condenser fan workings because I took it out and hooked it up to 12v power and the motor came on. I took the thermo switch off and grounded it with no luck. I also grounded the blue/white ground wire coming out of the a/c fan relay and not luck there. It is supposed to run to the pcm and the pcm should ground it to turn on the a/c fan.

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The cooling fan motor should have about a 6 amp draw. I cannot find the amperage draw for the condenser motor. Is the thermo switch you are talking about the one off the back of the engine?

Quote:

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Originally Posted by Strider

I tried to type this up as best I can. If something doesn't make sense plz let me know.

Thanks for all suggestions.

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I just replaced both of my fans. My cooling fan had only a 3 amp draw. And it would only run intermittently. I think there was a dead spot in the motor that would not allow it to start if the fan stopped on the spot. Since I was replacing the cooling fan on my 125,000 mile car, I decided to replace the condenser fan at the same time.

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Jumper in TEN and GND, both fans should run when the key is on and the accelerator pedal is depressed. When I am working by myself, I use a shortened broom stick jammed between the pedal and the seat to hold the pedal down.

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Yeah, I did that. I just pushed the throttle body cable back to simulate the gas pedal being pushed down and only the cooling fan came on.
I hooked up the condenser fan to a 12v bat and it ran just fine. Are you saying it's bad in that it is now needing more voltage to run now?

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The cooling fan motor should have about a 6 amp draw. I cannot find the amperage draw for the condenser motor. Is the thermo switch you are talking about the one off the back of the engine?

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Yes that is the thermo switch I am talking about. I pulled off the connecter and grounded it. I read that to test it was to ground it and see if the fan comes on. I didn't get anthing kicking on but when I do the jumper trick the cooling fan atleast comes on. Could it be the PCM that is bad? Winter is coming so I don't have to worry about it too much then but I want this fixed before next summer.

Thanks

So no one has any other ideas on what it is? How hard would it be for me to just run the fans off a switch in the cabin? That way I can just turn them both on and off when I want. I just don't quite know how to run the wiring.

Lots of good stuff here - http://www.miata.net/garage/CoolingSystemProblems.html

My car had the same issue and mine also ended up being the Fan YMMV.

Did you check that you had voltage to the fan??

If you decide that it's your fan(s) and at any point want to junk your old fans please consider checking out my blog post about reconditioning the fan first. I can't say it's your problem, but if it is, it would only cost you a little time and a few bucks. Especially since the cooler weather is making it more pleasant to work in the garage!

Regards.

http://www.dfwmiata.com/entry.php?12-Radiator-Cooling-Fan-Recondition

ps. Sorry about plastering a copyright all over the pics. One of these days I need to make them less annoying.

Yea, I haven't checked if I get any voltage. My meter quite working so I need to put another bat in it I think. LoL. but I did hook the fan up to 12v and the motor ran good, and if I got even a little voltage I would see the fan work. Although I have read that the connector can go back so if I am getting voltage I know the connector is bad. I hope. I just don't understand why my Cooling fan comes on with the a/c but not when the car overheats and my condenser fan doesn't come on at all. LoL

Thanks for the links guys. Like Piff said it is getting to nice weather and I would like to get it fixed now before it gets too cold. One thing I can't stand.