High Speed Fan Works, Low Speed Doesn't - Ford Mustang Forums : Corral.net Mustang Forum
 
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post #1 of 10 Old 02-25-2003, 08:12 AM Thread Starter
 
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Angry High Speed Fan Works, Low Speed Doesn't

My low speed fan does not work. The car will get to "M" then the high speed will kick on. I never see the low speed kick on.

The only time the low speed fan works is when I do the KOEO test. During the KOEO test, I see and hear the low speed and high speed fan cycle.

What could be the problem? I just don't have a clue here!

Thanks!

Pete

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post #2 of 10 Old 02-25-2003, 12:19 PM
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Low speed wire is fried. I've already been thru this. It may look OK but high voltage has most likely messed it up. Cut, splice and manually plug it into the fan with a female connector.


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post #3 of 10 Old 02-25-2003, 04:20 PM Thread Starter
 
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Yeah that maybe the case for some people. but "It does turn on when I run the KOEO test." If the wire were messed up wouldn't it not turn on at all?
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post #4 of 10 Old 02-25-2003, 07:33 PM
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Try replacing the Coolant sensor. It's happened to me twice in the past where my low speed fan wouldn't turn on anymore, and the first time, for months, I couldn't figure out what was wrong. Turned out to be that stupid sensor. It's real cheap at Autozone for like $16, and you get a warranty on it. If it goes out again, go go replace it for free.
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post #5 of 10 Old 02-25-2003, 07:46 PM
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i have the same problem. are you talking about the coolant sensor for the temp guage or the ECT sensor?

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post #6 of 10 Old 02-25-2003, 08:57 PM
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Quote:
Originally posted by 5ptSlow
i have the same problem. are you talking about the coolant sensor for the temp guage or the ECT sensor?
THe electronic coolant temperture sensor (ECT). It's right next the thermostat housing. Just unplug it, unscrew it out, put the new one, and you are set to go. The temperature sending unit is what controls your guage inside the car. It's wierd how it all works out, but basically, the sensor signals to the computer that it's at __ temperature, and kicks on the low speed fan. If the sensor is no good, the sensor won't signal anything to the computer, and you will start to overheat. The high speed fan will kick on after a certain point though because the sensor will start to get extremely hot, and get the hint that the fan needs to be turned on. Niether fan speed will work if the sensor is just plain out bad.
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post #7 of 10 Old 02-26-2003, 01:41 AM Thread Starter
 
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95GTfiveOh,

So you are saying you had the low speed fan not work, then you ran the KOEO test and the low speed did work? Then you changed the ECT sensor and everything was fine? If so then that's my problem.

I have both low and high speed KOEO test, but with the car running, only the high speed fan works.

Pete
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post #8 of 10 Old 02-26-2003, 09:19 PM
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When I had the fan problem, I never thought of running the KOER test, until a couple of weeks later. For some reason, the fan seemed to work only during this process, and not when normally driving. I was very suprised how that little piece of crap sensor was the problem all along.
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post #9 of 10 Old 02-27-2003, 01:41 AM
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that's wierd cause when my fan didnt work at all, i changed my ect sensor (40 bucks) and i dont remember my low speed fan ever working.

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post #10 of 10 Old 03-16-2003, 09:39 AM
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[QUOTE]Originally posted by 95GTfiveOh
[B]THe electronic coolant temperture sensor (ECT). It's right next the thermostat housing. Just unplug it, unscrew it out, put the new one, and you are set to go. The temperature sending unit is what controls your guage inside the car.




the ect does not run the gage
there are 2 sending units the one near the thermostat housing tell the computer the coolant temp
the one screwed in to the lower intake with one wire runs the gage.
this is what the computer sees in the stock program
ECT1_HS_FAN_ON 224 # ECT1 to turn on HS cooling Fan
ECT2_HS_FAN_ON 228 # ECT2 to turn on HS cooling Fan
ECT_HS_FAN_OFF 220 # ECT to turn off HS cooling Fan
ECT_LS_FAN_OFF 204 # ECT to turn off LS cooling Fan
ECT_LS_FAN_ON 208 # ECT to turn on LS cooling Fan


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Last edited by slantman; 03-16-2003 at 09:42 AM.
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