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Fans only work when AC is on

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If you're talking your cooling fans (engine) I'm not knowledgeable enough to help. I had a problem with my AC controls and blower motor where I had no defrost, AC, or nothing period. Blacksheep pointed me in the right direction and I checked the blower motor relay under the dash. Presto, fixed it. Good luck to you. Smart folks here, someone should be along to give you a starting point.
 
Wish I was knowledgeable enough to help you with this. My problem was as I stated in the post above. I'm guessing you've checked the obvious like the relays. Hope you get it resolved.
 
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Well that is neat that other folks like their engine to run hot, personally I'm going to adjust the fan curve with HPTuners so that (depending on ambient air temp) they kick in well before 220F ECT.
You're referring to the radiator cooling fans. The A/C should kick them on, if you have a port for a mechanical gauge, or, are able to see what temp the ECM sees, then you can check that they actually come on when they should. You need to be mindful that simply turning the fans on earlier may not solve any cooling issues. You still need to consider the thermostat and coolant volume as well. Too low a thermostat and you'll get bad mileage and lousy emissions, so I don't think I'd go lower than a 180..ish for a system that came with a 195 stat .Mishimoto seems to have a wider variety of stats with regards to temps, than anyone else, and they seem to be of good quality.
If the fans don't come on, you might want to check the pin connectors in the fusebox underhood. The S197s had some issues there, but they were fixed by the time your car showed up.
 

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