TwinCharged RX7

iTrader: (14)

Hi all,

I'm rewiring my car so that it utilizes the ECU a bit better.

I'm keeping the stock fans, but want to do away with all of the big relays in the engine bay. I'll want to simplify it to basically be off or on, and my ecu will control a relay that gives the fans power.

So my question is, which wire on the fans is ground (probably black), and which wire is the high speed power. I'll use these two, and the others i will delete.

Thanks.

oyvindjs

iTrader: (4)

i asked something borderline same, and karack answered me here:

https://www.rx7club.com/3rd-generation-specific-1993-2002-16/rx-oem-fan-can-turned-into-push-fan-995932/

RENESISFD

iTrader: (13)

Right in the FSM man

TwinCharged RX7

iTrader: (14)

Still having trouble figuring out which is for hi and which is for low.

Looks like:
Relay 1: provides power to both fans
Relays 2 and 4: provide power to each fan individually (maybe this is for hi so an relay is needed for each fan?)
Relay 3: Let's the fan motors pull to ground once the thermo switch allows it too.

But that seems strange because the black wire on each fan is already a ground.

RENESISFD

iTrader: (13)

This should explain it well. From the service highlights manual.

TwinCharged RX7

iTrader: (14)

Awesome, thanks.

So it looks like the only way to get the fans to be on high is to wire the two powers together and wire the two grounds together.

Andre The Giant

iTrader: (21)

There was some previous conversations about running the fans on high speed only, affecting the life of the motors/bearings. Also, don't you think that they are pretty loud on high? I run mine on medium using a switch to control 2 aftermarket relays. And I think they are pretty noisy at that speed. I know the full blast would get on my nerves

GoodfellaFD3S

iTrader: (213)

For those of us peons with the 'standard' fan wiring, I've found the best way to get them to come on high is to use the FC thermoswitch for some 97 F lovin' on track

mono4lamar

iTrader: (32)

All familiar faces in this thread. Here's how I could possibly help. High setting can only be achieved by the FC thermoswitch. Having a Power FC simply will not do it as you cannot change the point of the physical FC sensor thermoswitch.

If I were to wire up a different set of fans I would move away from the factory fans and move to slim 1550 cfm fans. I would then ditch the factory relays and get some simple ones from an auto parts store and use those (they all act the same) in a different location. Use the "relay 1" as your panic switch on the dash. Relay's 2 and 4 act in the same fashion so you can further simplify things by using only one or the other. Now your heavy hitter if you ever had one is relay 3, he has the job of the wing man. His job is to look after the thermoswitch operation so you'll surely want to keep him if things get out of hand.

That should be more than enough info, if you need more post. PLEASE don't PM me...

TwinCharged RX7

iTrader: (14)

I'm switching over to having my Electromotive TEC GT ecu control everything, and doing away with all the wiring that has been hacked up over time. Also, this should aleviate me needing a thermosensor.

My ECU has auxiliary outputs, which can be configured to turn on at certain temperatures. I only want to use 1 output, as I've only got 8, and am using all the rest on other things. I was thinking I'd turn the fan on high whenever it's needed. Seems like in order to get it on high, you need 12V to each of the power feeds on it, which I can do.

But if running on high is too stressful for the fans, would running on medium be ok to do? Is the high speed function really needed? My cooling system is much better ducted and I have a better radiator than stock, so maybe I don't need high anyways?

RENESISFD

iTrader: (13)

^ You will be making more heat than the stock system and if you plan to track the car I think it would be in your best interest for you to have the ability to run the fans on high.

You could always re-wire a few of the wires and relays so that when the ECU triggers the fans they come on at the medium speed and if you use the thermoswitch of your choice (FC or FD) then they come on high.

mono4lamar

iTrader: (32)

TwinCharged RX7

iTrader: (14)

Actually, I think I'll probably stick with medium. Life of the fans will be better than if I wired it on high all the time.

And even at the track, high would never come on unless you turned the AC on. Plus on the track the ductwork should be doing most of the work. If temps start to creep up, I'll just wire in the other set of wires and keep them on high.

indio84

iTrader: (7)

Ok would like to run my radiator fans on high, is this the right way to do it? and by doing this eliminate all thos relays? Which are all hacked up from all those years.