both cooling fans on constantly

[apimom]

My 1999 Impreza seems to have cooling fans running constantly even in freezing winter weather. Changed temperature switch on intake manifold - no change although the old switch looked like it was in need of changing.

Temperature gauge always in the middle since before this fan issue and now with the fans (both) running almost constantly. Cooling level ok.

There seemed to have been a major issue with this on two other Subaru models beween 2004 to 2007 that involved a relay that eventually damaged the ECU - recalls, warranty repairs, etc. No mentioning of Imprezas having this issue.

Any suggestions what I can check?

Also 2nd time in 3 months check engine light that showed no error code and went away after reset at the dealer. It is not the gas cap as I watch that issue like a hawk.

Any ideas and/or sugegstions appreciated.

apimom

[EvoEatr]

How many miles are on the vehicle? There was I believe a recall for that for some 05 Legacies....apparently the relay would stick and in extreme cases fry drivers in the ECM...I would say check your relays...Perhaps you have a wire shorted to a constant 12V source..Which coolant temp sensor did you replace? the one for the gauge or the one for the ECU? Are you sure you dont have any air in the system and the system is full of coolant? Have you changed the thermostat? The next time the CEL comes on..read the code...there has to be one....the only exception to this is if the diag. connectors are plugged in and in that case the CEL will be flashing...

[apimom]

High mileage, wire shortened possible. Had to be recent through driving vibrations. ECU sensor, System bled by professional. Coolant level checked before and after.

Thermostat is a possibility but then wouldn't I see the gauge move at least a bit sometimes. That needle is in the middle like painted on while driving. Car heats superbly I have to say.

Have to have the diagnostic done at a dealer - no can do at home....

Thanks for the fast reply

apimom