Cooling fan relay?
09-05-2006, 02:18 PM
#1
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Cooling fan relay?
My fans dont shut off. Did a search.
Confirmed the fuses are OK so I removed the relay.
I will be at a DE on Friday and Saturday. If I borrow a relay from another post 85.5 944 or 944S, is it the same?
If they shut with the borrowed relay, I will order the switch/sensor.
Of course the fans didnt shut the next time i shut down the car after having it
teched.
So, will any year relay fit?
Confirmed the fuses are OK so I removed the relay.
I will be at a DE on Friday and Saturday. If I borrow a relay from another post 85.5 944 or 944S, is it the same?
If they shut with the borrowed relay, I will order the switch/sensor.
Of course the fans didnt shut the next time i shut down the car after having it
teched.
So, will any year relay fit?
Last edited by Tom R.; 09-05-2006 at 03:29 PM.
09-05-2006, 03:03 PM
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same problem here, i was told it could be the coolant temp sensor on the rad? i tapped the sensor lightly with a hammer, and it fixed it for the time being, but its back now. time to replace it! However this may not be the same problem as yours
09-05-2006, 03:12 PM
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Do the fans switch down to low speed when you turn off the ignition? if so, the relay is OK and your culprit is the thermal switch in the rad. If they keep running on high speed, the relay is at fault.
09-06-2006, 09:46 AM
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There is a fairly simple test procedure on clark's garage which explains how to test the temperature sensor. Cross your fingers that the issue is the temp. sensor, it's ~$20 vs. ~$150 for the relay.
09-06-2006, 10:06 AM
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Not sure if it's the same thing on a 944 as a 968, but there are two ballast resistors for the cooling fans. They are two large circle resistors mounted on the firewall to the right of the battery. My car was running warm and cycling between slow and fast fan a lot especially after I shut it off. The connectors can become corroded, when I pulled the first connector off it crumbled in my hand. I replaced the shot connectors and cleaned up the connections and now the car runs cooler and only the low speed fan is on after I turn the car off.
09-06-2006, 10:22 AM
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Originally Posted by Epic2112
There is a fairly simple test procedure on clark's garage which explains how to test the temperature sensor. Cross your fingers that the issue is the temp. sensor, it's ~$20 vs. ~$150 for the relay.
At lime rock this friday I wanna just borrow (cant say pull or grab) Dan's relay when he hits the latrine and pop it in my car. if the fans shut off i know it is the relay. if they keep going it is the sensor.
I dont want to kill his relay since he has an S and I have an S2 and he is finding out about this as he reads this post.
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09-06-2006, 02:02 PM
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Originally Posted by arbeitm
Looks like they are the same from 87 and up. So it should be fine.
And if you screw Dan up....don't tell him that I said it was ok.
And if you screw Dan up....don't tell him that I said it was ok.
you going to nassau this sunday? i will have the miata unless there is very little tire left on the S2.
09-06-2006, 02:07 PM
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Originally Posted by PeteL
Fans running after shut down is usually the temp sensor on the rad. Not the relay.
It is a kinda' built in fail safe.........the thermal switch fails in the mode to still send a signal to the relay ("FANS ON") to protect the car from overheating when it fails. So fans run all the time, even with ignition "OFF"..
Since the relay is there to switch the fans "ON", if there is a problem with the relay, the fans usually don't run at all.
09-06-2006, 02:11 PM
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Originally Posted by Tom R.
The secret is safe with me. you going to nassau this sunday? i will have the miata unless there is very little tire left on the S2.
you going to nassau this sunday? i will have the miata unless there is very little tire left on the S2.
09-07-2006, 01:06 AM
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When my thermal switch started to go it was very intermittent. So disturbing anything electrical in the fan circuits may turn them off at least temporarily. So swapping out the relay may not be a definitive test.
I also agree with the others that said a relay failure wouldn’t leave the fans on. If you do replace the thermal switch just remember that the part of the radiator that it screws into is plastic and can break if you aren’t careful. It can also just break if it is getting brittle.
I also agree with the others that said a relay failure wouldn’t leave the fans on. If you do replace the thermal switch just remember that the part of the radiator that it screws into is plastic and can break if you aren’t careful. It can also just break if it is getting brittle.
