LS1 ECM low high fan signal question, Taurus fan
03-02-2016, 09:22 AM
#1
LS1 ECM low high fan signal question, Taurus fan Hey Guys and gals-
I'm wrapping up the electrical for my LS swap into my 73 nova. I am using a single motor 2 speed Taurus fan and have a couple questions.
1. Does the 02 LS1 ECM activate both the "low" and "high" fan signals at the same time?
2. Does anyone know if it will hurt the Taurus fan to have the "high" and "low" pins energized at once?
Thanks.
I'm wrapping up the electrical for my LS swap into my 73 nova. I am using a single motor 2 speed Taurus fan and have a couple questions.
1. Does the 02 LS1 ECM activate both the "low" and "high" fan signals at the same time?
2. Does anyone know if it will hurt the Taurus fan to have the "high" and "low" pins energized at once?
Thanks.
03-02-2016, 11:01 AM
#2
I may have found my answer:
So since my 75AMP relay is only a 4 terminal, I'll need to do this:
The Taurus fan is designed for a low/high operation. Feed one power wire (don't know the colors off the top of my head) and you get low, feed the other power wire and you get high. That all works great, when it's controlled by the FORD PCM, but not the GM PCM.
See, when the Ford PCM wants low, it grounds the low fan relay coil and for high it removes the ground on the low relay and puts the ground on the high coil. But when the GM PCM triggers the low fan, it sends a ground to the low fan relay coil. When it goes to high fan, it ADDS a ground to the high fan relay coil while leaving the ground on the low fan coil. So, this means both relays are actuated AND both low and high fan motor coils are engauged.
This essentially makes the low and high fan motors work against each other and you got more of a 'medium' speed. Probably isn't good for the fan motors either.
Here's the fix. Run the low relay control through a relay BEFORE it goes to the low fan relay. This second relay needs to be spliced into the the high relay control wire so that the low relay control wire is interrupted when the high fan relay control comes on.
See, when the Ford PCM wants low, it grounds the low fan relay coil and for high it removes the ground on the low relay and puts the ground on the high coil. But when the GM PCM triggers the low fan, it sends a ground to the low fan relay coil. When it goes to high fan, it ADDS a ground to the high fan relay coil while leaving the ground on the low fan coil. So, this means both relays are actuated AND both low and high fan motor coils are engauged.
This essentially makes the low and high fan motors work against each other and you got more of a 'medium' speed. Probably isn't good for the fan motors either.
Here's the fix. Run the low relay control through a relay BEFORE it goes to the low fan relay. This second relay needs to be spliced into the the high relay control wire so that the low relay control wire is interrupted when the high fan relay control comes on.
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03-05-2016, 06:13 AM
#8
If you are worried about amp rating than hit a salvage yard and grab the relays from a donor car. Surprising how small they seem, the factory ones are almost certainly not 75 ampers.
By the way, if your car is anything like mine you may not need the high speed. I wired mine in but never got around to hooking up a control sensor.