please help with thermo fans question
 

i'm currently doing an engine swap in my forester that requires me to put in a gf8 wiring loom.....

my forester thermo fans have 2 wires to power each of them

my gf8 loom has 3 wires to power each thermo

i've mucked around with both gc8 and forester sets of thermo's off the car and discovered that the both sets of thermos can be powered up by just connecting the black wire to the earth and the blue wire to the positive, that leaves me with the green wire off the loom just doing nothing

now my question is.... what is the green wire for, maybe an over-ride power-on for when the a/c is switched on?

so how do i go about wiring this 3 pin plug up to my forester thermo's to keep them fully functioning?

i've thought about using the gc8 fans but will require quite a bit of mucking around to fit my forester radiator, i'm not too keen on buying a gc8 radiator as then i will have no way of bolting my overflow tank to it and i'm slowly running out of cash here having to buy this that & the other

any help muchly appreciated

The 3 wire fans are 2 speed fans....GC/F ECU(and everything else I`ve seen WRX/lib) has hi and lo speed fans....seems your fozzy doesn`t.

With-out looking at the various wiring diagrams .. I would think that you would need to connect the green and white wire from the loom to the active wire of you fozzy thermos so when the ECU wants to run either speed you fans will run/do something.

Alternatively using the WRX fans might be the best idear..if they fit.

yeah thats sort of what i was thinking, so there will be no drama's of anything shorting out in the loom if i connect the blue and green wires together and then to the blue wire of the foz thermo's?

maybe on the foz it powers up the fans individually when needed instead of varying the speeds? i dunno

Should be done thru a relay/separate circuit so back powering it shouldn`t hurt.....but I`d test it with a multi meter first just to be sure ;)

yeah the back-powering bit is what i'm worried about, like if only 6v comes out of the blue wire and i connect it to the green wire which could be throwing out say 12v and end up sending 12v back up through the blue wire

so yeah couple of relays hey, great idea, will have a play with the multimeter and see what its throwing out of each wire once they cut in or when the a/c is switched on

wish i hadn't just bought a new foz radiator last year, would make it easier to just go and buy an all ally gc8 ones that i could just bolt the gc8 thermo's onto & bolt it in be done with it LOL

I think I have a spare set of fan motors from a GC8, will have to check.
Is there a way you can use the GC8 fans in the foz housing?

cheers but i already have a set, they don't bolt onto the foz radiator unforunately, i've also considered trying to re-mount the gc8 thermo's into the foz shrounds but the bolt pcd is different and they are recessed differently... don't want it ending up looking like a dogs brekky ;)

been trying to brush up on my lekky skillz (i have none) and i'm thinking if i just used diodes it the blue and green wires off the gc8 loom and then jointed them to the foz single blue wire, this will stop any 'back current' flowing up either wire from the other one.... does that even make sense?

just use some high current diodes on all of the positive feeds.

cool, you can explain it to me when i see you tomorrow or tuesday jeff, you can just buy them from jaycar i'm guessing?

done a bit of googling and it seems that i need to put a 1N4004 (1A 400V) rectifier diode in all positive feeds yeah?

Chris

As your using the Link, it does not utilise the dual speed nature of the fans. You should only wire up the high speed coil of both fans independantly, as they are both controlled seperatly from the link, i.e two when it is very hot, one otherwise. You can just use your existing fans to achieve this. The A/C will also switch on a fan.

Also, under no circustances should power you both the low and high speed windings at the same time, this won't end well.

Hope it helps.

cheers brad, you wouldn't happen to know which is the high & which is the low off the gf8 loom....... pick a colour - green or blue?

i guess when i get it started i can throw a multimeter on there to ascertain this

got a couple of other small questions for you too mate...

the snipped wire labeled 'back-up power' near the link ecu plugs... where does this wire go to?

power for the plx wideband (small black and red wires that plug into the plx module)... does this connect to the small plug (with red and black small wires) that plugs into the link?

will hopefully be firing your old girl up in the next day or so :)

[QUOTE=Strubaru;425733]

will hopefully be firing your old girl up in the next day or so :)[/QUOTE]
Yew!!

Nice pun, intended or othewise.

The red and black wires for the PLX are just 12Vdc and GND. Use any ground here, but the one near the ECU is probably as easy as any other. I can't remember where I pulled the 12V from, probably the ciggy lighter since I don't smoke and it's already fused.

I'm not 100s on the "back up power" wire. The Link doesn't use backup or hold power in this config, so I dare say your safe to leave it alone.

I can't guess (well I could, but I shouldn't) on the wires on the fan, but if you had them spinning with two wires then I'd use them, they can always be switched later if necessary anyway.

cool cheers mate, will do that

what pun? :confused:

all sorted, for anyone elses future reference, the green wire on the thermo's is high speed, blue wire is low speed, black is obviously earth ;)

Another life saving thread