my dual fan set-up is not functioning properly. the driver side fan works as intended but the other one does not work when it should. i checked the relays and they are fine. if you give the fan a ground it works but something is not telling it when to come on . any help?

 

what temperate are you running? can you give a little more info about this?

 

it runs about 160 while driving. but when you sit still it will rise . i have let it go up to about 220 and it still wont come on. so i am stumped. i checked the relays and i think they are good. i put a new switch in it. that didnt help. if you ground the fan it will work. to do this touch the wire to the switch to anything. and the fan takes off. help please

 

I was poking around at work a while back, and I looked up the stock spec for the secondary fan switch on a dual fan setup.. It was something like 238*...

I'll see if I can double check that and confirm that figure tomorrow (or if anyone else knows for certain??)

 

i have the same problem w/ an 87 305 tpi
the passenger side fan never comes on but the drivers side one works fine
thirdgen88, id like a confirmation on that stock setting for the second fan to come on
any other input would be welcome

 

Well, confirmation you have! I actually did some research today at work.. The stock radiator fan switch for a dual-fan system is a normally open switch that closes from 240*-252* (this is from the GP Sorensen specifications guide).. See my other post for optional fan switches...