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  #1  
Old 07-09-2007, 08:35 PM
awdbaby awdbaby is offline
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cooling fan problem

Soon as I turn my key on both cooling fans come on even with the climate control off! Thanks, steve
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Old 07-10-2007, 01:15 AM
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Quote:
Originally Posted by awdbaby
Soon as I turn my key on both cooling fans come on even with the climate control off! Thanks, steve
As a first test, disconnect the water temperature sensor. The usual suggestion towards locating it is to, look under the alternator. If the fans stop running you have located the cause, i.e. a faulty sensor. Also check here for wiring or connector damage, which could be causing a short circuit.

The overall circuitry is quite complicated and involves several relays located in the distribution assembly, within the engine compartment. You could try removing these one by one, as a second test in an effort to locate the fault.
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Old 07-10-2007, 02:31 AM
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On my Legacy, disconnecting the water temp sensor causes the fan to turn ON. Is the SVX different?

Also, the sensors under the alternator are for crank position. The water temp sensor is under the intake manifold at the back on the drivers side (assuming LHD).
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Last edited by b3lha; 07-10-2007 at 02:40 AM.
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  #4  
Old 07-10-2007, 05:12 AM
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Quote:
Originally Posted by b3lha
On my Legacy, disconnecting the water temp sensor causes the fan to turn ON. Is the SVX different?

Also, the sensors under the alternator are for crank position. The water temp sensor is under the intake manifold at the back on the drivers side (assuming LHD).
Greeting Phil and thanks for your input.

The control circuitry could very well be arranged as you suggest, in which case the test is to bridge the two sensor connector terminals and note if the fans stop running. Also look for an open circuit or bad connection rather than a short. The schematic appears to indicate a thermocouple, something I had not expected and have doubts about.

I was dubious about the sensor position I had seen advised by another, hence my wording. Apologies and thanks for the correction.

I sincerely hope that confusion is now not the end result of my post.

Cheers, Trevor.
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Old 07-10-2007, 06:48 PM
awdbaby awdbaby is offline
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Quote:
Originally Posted by Trevor
Greeting Phil and thanks for your input.

The control circuitry could very well be arranged as you suggest, in which case the test is to bridge the two sensor connector terminals and note if the fans stop running. Also look for an open circuit or bad connection rather than a short. The schematic appears to indicate a thermocouple, something I had not expected and have doubts about.

I was dubious about the sensor position I had seen advised by another, hence my wording. Apologies and thanks for the correction.

I sincerely hope that confusion is now not the end result of my post.

Cheers, Trevor.
Thanks for your help, I will try crossing the connectors tomorrow.
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  #6  
Old 07-11-2007, 06:54 PM
awdbaby awdbaby is offline
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Hi guys, I tried bridging the wire conector on the temp sender and all that happens is the relays make noise. Any other ideas, where is the thermocoupler located? thanks steve
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Old 07-12-2007, 12:46 AM
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Quote:
Originally Posted by awdbaby
Hi guys, I tried bridging the wire conector on the temp sender and all that happens is the relays make noise. Any other ideas, where is the thermocoupler located? thanks steve
You have not quite understood my reference to a thermocouple which was in relation to the make up of the sensor. No additional separate component exists for you to check.

About all you can do is try removing relays as I have suggested, as a means of possibly localising the fault. Delving deeper will require in depth knowledge. Meantime follow your nose and look for a possible wiring, or connector fault.
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  #8  
Old 07-12-2007, 07:21 AM
awdbaby awdbaby is offline
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Hello, yes I see the temp sensor and thermocoupler are the same. I thought you knew something I didnt. I did pull relays when the fans are on and fans do shut off. I will tear into it more just a matter of time. Thanks for you help, steve
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