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I have a '94 968 Cab. Last night, the cooling fans did not turn off and my son noticed them running an hour later.

I pulled the fan relay and of course they stopped. Does anyone have a quick idea on isolating the fault between the sensor and the relay?,

Thanks
<!--quoteo(post=70561:date=Apr 19 2009, 08:05 AM:name=jrallen01)-->QUOTE (jrallen01 @ Apr 19 2009, 08:05 AM) <{POST_SNAPBACK}><!--quotec-->I have a '94 968 Cab. Last night, the cooling fans did not turn off and my son noticed them running an hour later.

I pulled the fan relay and of course they stopped. Does anyone have a quick idea on isolating the fault between the sensor and the relay?,

Thanks<!--QuoteEnd--><!--QuoteEEnd-->

The 92 Cab I got last July exhibited a similar problem the day I went to see it. Turned out the relay had failed "closed" (preferred failure condition I'm sure) causing the fans to always run. The PO replaced the relay with a new one - and the problem went away immediately. The rest is history. Good luck.
<!--quoteo(post=70561:date=Apr 19 2009, 06:05 AM:name=jrallen01)-->QUOTE (jrallen01 @ Apr 19 2009, 06:05 AM) <{POST_SNAPBACK}><!--quotec-->I have a '94 968 Cab. Last night, the cooling fans did not turn off and my son noticed them running an hour later.

I pulled the fan relay and of course they stopped. Does anyone have a quick idea on isolating the fault between the sensor and the relay?,

Thanks<!--QuoteEnd--><!--QuoteEEnd-->


<!--quoteo(post=70561:date=Apr 19 2009, 06:05 AM:name=jrallen01)-->QUOTE (jrallen01 @ Apr 19 2009, 06:05 AM) <{POST_SNAPBACK}><!--quotec-->I have a '94 968 Cab. Last night, the cooling fans did not turn off and my son noticed them running an hour later.

I pulled the fan relay and of course they stopped. Does anyone have a quick idea on isolating the fault between the sensor and the relay?,

Thanks<!--QuoteEnd--><!--QuoteEEnd-->
I pulled the case off of the relay and could see the contacts move back and forth. Points look good. I replaced the case and finally located the Fan Sensor on the driver's side of the radiator right below the upper hose. It's a bear to get at it and disconnect the wire. The fans no longer run.

I am assuming a high probability of $11 thermal fan sensor failure.... and not the $168 relay.

Thanks for the reply.
<!--quoteo(post=70570:date=Apr 20 2009, 12:59 AM:name=jrallen01)-->QUOTE (jrallen01 @ Apr 20 2009, 12:59 AM) <{POST_SNAPBACK}><!--quotec-->I pulled the case off of the relay and could see the contacts move back and forth. Points look good. I replaced the case and finally located the Fan Sensor on the driver's side of the radiator right below the upper hose. It's a bear to get at it and disconnect the wire. The fans no longer run.

I am assuming a high probability of $11 thermal fan sensor failure.... and not the $168 relay.

Thanks for the reply.<!--QuoteEnd--><!--QuoteEEnd-->

I have a 94 cab and had the same problem last year. Relay was fine --> I simply disconnected the battery for some hours to reset the DME. No problem anymore since then. I ordered a spare thermal sensor but still didn't change it.
Goor luck.