Got most of the wiring figured out, but the pinout chart for the 04 GTO only shows one connection (GREEN connector, #33, "High Speed Cooling Fan Relay Control"). I'm using two fans and would like to have them staged on temp. I'm new to the PCM world - any help is appreciated.

2004 GTO, LS1/T56, stock, w/PCM & harness going in 2000 Miata

-Ray

 

Is there 3 Relays with that setup from the Factory..as in do they have a low and high speed?

 

Its a pin thats not used from the factory in the 04 GTO PCM.

Blue Conn. Pin #42 : Low Speed cooling fan relay Control

Green Conn. Pin #33: High speed cooling fan relay.

I'm using a PCM from an 04 Yukon with a modified 04 GTO flash, and it is pretty much just hook and go. Works great.

You can wire them with 2 or 3 relays, but that's your choice. I'm actually looking at doing mine with a 3rd relay, even though my 2 are working fine.

 

Great stuff guys. Thanks for your help!

-Ray

 

The 3 Relay setup is very easy to wire in.

 

How was the rest of the wiring?

 

I have the same problem mentioned above, but let me see if I understand what you´re suggesting, you are saying that i can use the Blue 42 pin and the 2 realy configuration and it will work? I´m also using a 04 gto pcm.

Regards

 

You can wire it with 2 Relays..but it's going to be to where it's one Fan on high..then when the 2nd one kicks on it's going to be high speed also. There will be no low speed.

 

.. ok maybe a scheme will explain better? please?

 

For high and low speed you need three relays. Here is a chematic for an f-body. You would just need to use the correct high and low signals instead of how they are listed here. I believe that same schematic is in the fac's somewhere with the relay pin numbers marked on it.

 

ok great info, but the only difference is that the low fan speed signal is not from the PCM on the GTO PCM, any way thanks for the diagram. Anyone else thay may help?..What alternative do I have? Control de fans not with the PCM?

 

The PCM doesn't control the Low Fan setting?

 

the PCM pin 42 is not used... not cable..
on the gto de BCM (body control module) controls de low speed fan.., any alternative method to thw low speed fan?

 

use a stand-alone setup with a radiator probe for the smaller fan(on high)then run a relay for @2nd fan(also on high) when the a/c comes on. i have the GTO fans, thats what i did. i didnt bother to use the 2 low settings

 

That's gay that the BCM Controls it.. is there a wire coming out of that Pin #42?

The reason I ask is something has to tell the BCM to turn it on at low setting..unless it goes off of the Temp and does it itself.

Try running a wire off of that #42 if there is nothing there and see what it does..

 

Has anyone confirmed that pin#42 will trigger the low spped fan relay?

Thanks

 

I have pin 42 off of the blue connector working as a fan turn on. From what I understand this has to be enabled in the tune. As it's done in the tune you can set either of the turn on signals to any temp you like so either can be low temp or high temp. Obviously you need to add a pin in that connector as it's normally unused in the gto.

 

In regards to Blue Pin #42, here is a great little tech article on the subject. Very informative.

Dual Fan Wiring Harness

 

As RHDV8 said, I can confirm that Blue #42 WILL WORK. That is how I have mine wired up, and it's been working for 2 years that way. You just have to make sure you go in and set the Fans setting to 2 fans under "System" in HPTuners.

 

Will this work in this application?
https://ls1tech.com/forums/conversio...l#post13568906