Electric fans with PSI harness

[elf w/capital T]

My controller is working, used on my sbc.

I went with an ls swap.

Now i have a PSI standalone harness.

Question is... I have two wires for a fan1 and fan2 GROUND....

with the fan controller being involved, where should i route these bad boys to?

I do want one fan on for engine temp, the other with ac on.

Vintage air is also involved and i have a trinary switch in all.

Anyone?

[mongocanfly]

Are you saying you have a seperate controller for your fans? On mine I run fan 1 and fan 2 thru the psi harness and the ecm controls both. My tune-up guy set them to come on at different temps. 20 degrees different between the two.

[elf w/capital T]

I have one controller and will have two fans. But the ecm harness has one wire per fan for GROUNDS. I don't think it would be okay to run them to the fans AS grounds...?? Maybe im just way over thinking it all...

[mongocanfly]

I may not fully understand what your asking ...on mine I have 2 relays,, fan 1 and fan 2.. those 2 fan wires are in the harness....fan #1wire to #1 fan relay to fan #1..and fan #2 wire to fan #2 relay to fan #2.I ran from one relay to one of the fans and the other to the other. Then the ground wire from the fans I grounded to the frame . I'd have to go look at my directions for wiring to make me understand what your asking..I can't remember what it showed. What are you referring to as a controller? Is that the relay? If you only have one relay you need a second relay to control them separately

[dwcsr]

What are The fans? single or two speed? How do you want the fans to operate? The PCM grounds are for relays not the fan ground.

[A1971Blazer]

You have to use fan relays because of the amperage draw from the fans.....the grounds in the harness to the PCM are there only to ground the relays...thus making the fans run. Two fans.......need two relays.
Don't ground your fans to those PCM connectors.

[elf w/capital T]

Okay, so i will be removing the fan controller all together and adding two relays...?

[A1971Blazer]

Originally Posted by elf w/capital T

Okay, so i will be removing the fan controller all together and adding two relays...?

If you have a stand alone controller...yes remove it and install 2 relays.
Google "dual fan relay wiring"......there are a few different ways you can wire it depending on how you want them to work and how the PCM controls them.

Here is a place to get relays cheap and they include a plug and pigtail.........
http://www.surpluscenter.com/Electri...SE-11-3222.axd

[clemsonteg]

Originally Posted by elf w/capital T

Okay, so i will be removing the fan controller all together and adding two relays...?

Yes. The PCM is doing the same thing that the controller is by controlling the temperature at which the fans are activated.

If it were me, I would add a 3rd relay for the trinary switch from the AC which can be used to trigger 1 or both of the fans depending on how you wire it. Essentially, the 2 fan relays will grounded by the PCM, activating the relays, and providing power to the fan. I am assuming that the output on the trinary switch is 12v, not a ground which is used to activate the fan relays, so the third relay would be in place to supply the ground to the fan relay(s) when the trinary switch provides the +12v to activate the third relay.

[elf w/capital T]

You guys rock. Thank you

[mongocanfly]

Elf my psi harness came with this relay setup for the fans.https://www.psiconversion.com/produc.../KIT-1010.html

[elf w/capital T]

Sheesh 50 bones for just one fan. Looks sharp and very easy to get the fans to work though! Thanks!

[mongocanfly]

Mine came with the harness. I didn't have to buy them separately

[elf w/capital T]

Lucky hahahaha

[mongocanfly]

I'm sure I payed for em but the guy I bought my ls engine from is a psi dealer and he let me have the harness and everything else at cost. So yeah a win win for me

[mongocanfly]

I'm sure I payed for em but the guy I bought my ls engine from is a psi dealer and he let me have the harness and everything else at cost. So yeah a win win for me

[clemsonteg]

I don't have a diagram of how mine is wired, but here is a breakdown of what I have. Each relay has 4 terminals numbered 30,85,86, and 87. For the first two relays, they will be wired similarly with the only difference being the wire from the PCM to control each fan. Here is how I would do it

30 - 12v battery power
85 - 12v ignition power (this is part of the coil trigger)
86 - ground control wire from PCM or AC relay discussed below (the second part of the coil trigger)
87 - positive fan connection

Essentially, the relay needs to see a power and ground on terminals 85 and 86 in order to trigger the relay and make the connection from 30 to 87 and supply battery voltage to the fan. The switch in this case is the ground that is supplied to the relay from the PCM to trigger the relay. The ground wire on the fan can be grounded to the frame.

To add control from the Ac system as well, a third relay is needed to convert the 12v trigger signal from the trinary switch (I'm assuming this is 12v, please verify) into the ground signal needed by the fan relay to switch the fan on. This is how I would wire the third relay:

30 - chassis ground
85 - 12v signal from trinary switch
86 - chassis ground
87 - connection to terminal 86 of 1 or both fan relays

I hope that all makes sense and that it helps.

[elf w/capital T]

Put it like that and yes, it does make sense, I'm always deterred with the symbols n what not. Thank you for taking the time to spell it out!

[clemsonteg]

Originally Posted by elf w/capital T

Put it like that and yes, it does make sense, I'm always deterred with the symbols n what not. Thank you for taking the time to spell it out!

No problem. If you find that the trinary switch supplies a ground signal instead of 12v, all you need to do is carry that to the fan relay without the need for a third relay. I'm assuming that since my binary switch is 12v, that the trinary switch is similar with the exception that the third post only activates at a certain pressure. I'm planning to have my second fan switch on when the AC is on.