Big Mark Posted March 23, 2016 Share Posted March 23, 2016 I need to locate a switched live in the engine bay to wire in a fan controller. Anyone know which of the many wires under the bonnet this would be? Quote Link to comment Share on other sites More sharing options...
berg Posted March 24, 2016 Share Posted March 24, 2016 What type of controller do you have? Only way ive seen fans wired is through a relay and a temp sensor in the rad which triggers the fans to come on and off Ive never seen any that need a switched live before All im thinking is i know these twin fans can pull close to 30amps so you may have to be carefull what you tap into depending what its for Quote Link to comment Share on other sites More sharing options...
Mk4Gaz Posted March 24, 2016 Share Posted March 24, 2016 Use the factory fan wiring to trigger a 40a relay. Depending on the fans you're using, you might even be able to use the factory wiring without a relay. Do you know the current draw of your new fans mark? Quote Link to comment Share on other sites More sharing options...
Big Mark Posted March 24, 2016 Author Share Posted March 24, 2016 What factory fan wiring? The factory fan is viscous? The only electric fan is the A/C fan which I was going to wire into the controller as the override, i.e. fans come on when A/C is on. Rather than mess about trying to work out the safest way to wire things I brought the Mishimoto fan controller http://lib.store.yahoo.net/lib/yhst-62631657248580/MMFAN-CNTRL-InstallGuide-proofed.pdf It has a live to the battery, negative to fans, ground, switched ignition source, and an override wire (A/C fan connection or manual switch for example). Not checked the current draw but fans, controller and radiator are all Mishimoto. Quote Link to comment Share on other sites More sharing options...
Mk4Gaz Posted March 24, 2016 Share Posted March 24, 2016 Yes the ac fan mate, that comes on normally when the coolant temp reaches 'x' degrees. Quote Link to comment Share on other sites More sharing options...
Big Mark Posted March 24, 2016 Author Share Posted March 24, 2016 I wasn't sure what triggered the A/C fan so didn't want to risk anything. Are you 100% sure that it is ok to run the Rad Fans from here? Quote Link to comment Share on other sites More sharing options...
Mk4Gaz Posted March 24, 2016 Share Posted March 24, 2016 Yes mate. Without knowing the draw of the new fans, you can just run a relay, and use the original live wire as the trigger. I'm running twin fans on mine without a relay, directly off the stock wiring. Mine are rated at 80w each. 160w/14v = 11.43a 160w/12v = 13.3a The original electric fan circuit is fused at 15a Quote Link to comment Share on other sites More sharing options...
Big Mark Posted March 25, 2016 Author Share Posted March 25, 2016 Made a start on doing lots of jobs on the car today. So there is a large electic fan on the front of the air con radiator and a tiny fan on a bracket on the back of the engine radiator. Obviously I connect my new fans to the the wiring for the big fan? What are these 2 fan actually for? The small one seems pretty pointless Quote Link to comment Share on other sites More sharing options...
Mk4Gaz Posted March 26, 2016 Share Posted March 26, 2016 I used the wiring from the small electric fan. The bigger fan is for the air con iirc, and the smaller one I believe, is a back up fan to aid cooling if the viscous fan stops working or isn't pulling enough air through to cool the system down Quote Link to comment Share on other sites More sharing options...
Big Mark Posted March 26, 2016 Author Share Posted March 26, 2016 oh ok. Little fan it is then. Quote Link to comment Share on other sites More sharing options...
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