Alright I know its been done before, but I have some personal wiring questions and am in need of suggestions. I am replacing my factory single fan on my LO3 with dual lt1 fans that I picked up cheap. I would like avoid using the factory coolant sensor as its half-way broken from header install. I can not write code for the fans because I still have the 8746 ecm. What I would like to do is have the fans on staggered temperatures both on and off, slightly lower than the factory 220º. I do not really want a manual only switch incase I forget or someone else drives, plus I like to keep the interior factory looking (however I might enjoy a manual switch in the engine bay for track duty). I have been using my A/c control as a fan switch lately, but in the summer I'm going to recharge it and use it. I would like some recommendations on what to use and keep the budget under $50 or so. Could I tap into the coolant gauge sensor in the drivers side for anything? Could I change the code for the AIR pump to run fans instead?

 

Glad, You might try posting your question on the electrical board. They might be of more help and have some diagrams for you. Just a thought.

 

I'd recommend picking up a Hayden adjustable fan relay from your local autoparts store. I have the stock switch (now converted to a lower temp) controlling one temp and the Hayden relay controlling the other one, works great!

Tony

 

Just get a flex-a-lite fan controller… it will allow you to set the fan temps using a **** under the hood and it doesn’t use the sensor in either head or manifold, it uses a temperature sensing bulb that is pressed against the radiator fins/tubes.

 

I use my ecm to control my cool. fan, but it requires coding changes. Some sort of mechanical controller would be easier.

 

someone posted a schematic for fan control using the temp guage sensor, with a small electronics board. That is probably do-able for around 50 buck, just build two versions, so you can set the two fans independantly. I'll see if I can find it, but try on the electronics boards any way, maybe try searching on 'fan controller' or something like that. Good luck! Otherwise, just run em both at the same time, and get a cylinder head temp fan switch ala a GN, or specific painless wiring or something out of jegs.summit. if i'm not mistaken, the GN one comes on around 190 degrees or so. these switches are like the factory one, just come on at a lower temp. thats how the dual fan cars operated anyway. another option would be to use that switch for one fan, and re-utilize the factory ecm control for the other fan.

 

https://www.thirdgen.org/techbb2/sho...fan+controller

yep, right under 'fan controller' searching. should do what you need.