LS3 Cooling
Thread Starter
Intermediate
Joined: Jun 2008
Posts: 29
Likes: 0
LS3 Cooling
I have a LS3 in my 69 and going to mount dual electric fans, can i run both fans through the stock tempsender and ECU ( 30A mega fuse ) or do i have to run one fan through the ECU and one through another sender and relay?
I donīt know the Amps on the fans.
I donīt know the Amps on the fans.
Burning Brakes
Joined: Oct 2008
Posts: 1,037
Likes: 14
From: Mobile Alabama
The ECU has the capability to send two fan signals. Not knowing your particular wiring harness, it should have two fan leads. They are a ground signal, and you don't run high current through the ECU. So - you need a relay for each fan. The signal from the ECU is the ground switch to the relay.
Burning Brakes
Joined: Oct 2010
Posts: 1,192
Likes: 7
From: Wentzville MO
Burning Brakes
Joined: Oct 2008
Posts: 1,037
Likes: 14
From: Mobile Alabama
That's why I said depending on your harness. With one lead, it would be the signal to trigger the relays. You may be able to use one relay for both fans, (depending on current), but one relay each is more reliable. This way both fans would come on at the temp set in the programing. If you want one fan to come on earlier or later than the ECU temp you could wire one to a temp switch - you can even find these that are adjustable. Whatever you do, don't use the ECU wire to directly run the fans. Good Luck
