You need some relays and a Diode... It's not horridle complicated... But for a dumbass like me, BUY A KIT! It's only like $40 for the controler with A/C relay from Flex-a-lite... And their directions are EASY, plug everything in... Done
I am about to install my 2 12"s (shrouded unit) I think I am going to put on with the A/C and the other with a temp sender... Not sure if I want them both on to cool the truck normally... Guess time will tell...
I got a really nice Temp sender deal, but the actual sensor is 3/8" NPT which is HUGE, everything on the motor is like 1/8" or 1/4" at most... So I think I am going to make a custom "upper hose" that has a 3/8" NPT bung in it... Could look trick, guess we'll see