RAD FAN WORKINGS?

KENC

Well-known member
ISDC Club Member
Lads dont have rad fans coming on, checked fuse and they grand, anyone no the workings of the two fans on jap impreza, 2 relays for sub fan 2relays for main fan. are they triggered off same sensor that sends signal to temp gauge in dash
 
Had a problem with rad fans before, turned out to be a bad earth on the main fan.

Anyway, the main fan will run if the engine temp hits a particular level but if the temp continues to rise the ecu will switch on the a/c fan also to reduce the temp
 
Could be but i'd start with the basics first, if the fuses are good then check the relays, if they're good, test the fan motors, if they work its the wiring or ecu, but i'd say its wiring
 
Where were you getting earth for fans? the motors are grand, and car is a bit of project so not straight forward, neither fans are coming on, and i tried to do that diagnostic mode thing by plugn in wires under dash, it ususlly brings on fan, but it didnt, think i done it right, is it black or green conectors?
 
[quote author=KENC link=topic=12761.msg156365#msg156365 date=1234568508]
Where were you getting earth for fans? the motors are grand, and car is a bit of project so not straight forward, neither fans are coming on, and i tried to do that diagnostic mode thing by plugn in wires under dash, it ususlly brings on fan, but it didnt, think i done it right, is it black or green conectors?
[/quote]

The earths for the two fans are: as you look down behind the rad, on the left chassis leg you'll see a black wire bolted to it, thats the main fan earth, the a/c fan earth is on the right chassis leg.

The diagnostics plugs are black for reading and black + green for reseting.

http://www.scoobypedia.co.uk/index.php/Knowledge/ECUReset
 
Glad you pmd me the reason for meeting, was getting worried you were wanting a manly love meeting :lol: i thin k you could be onto something, think today i provided an earth into relay with a tester an it closed another relay and started fan, how come there 2 relays per fan? which fan is ac, ds or pasenger side???
 
:lol: :lol: I charge extra for the manly love :whistle:

Cant remember why they've2 relays per fan, have the wiring diagrams at home and can post them up when i get back. Yeha the a/c fan is on the passenger side.

If the fan is working then test the rad wiring at the block connector with a multimeter, it should kick in just about half way on the temp gauge. You should get 12V one of the outside wires, the outher outside wire should have continuity with ground. the middle wire is a switch wire :thumbsup:
 
ok, tried a different temp sensor and still same, checked earths to body and they bolted tight to chassis leg, even tried different ecu and still same, i tried with a basic tester and wen car is running and over half way on temp gauge, there is no live going to fan connection block. :wall: :wall:
 
Each fan has seperate wiring and its unlikely that both sets of relays are faulty, swap the a/c relays with the main fan relays. See if anything happens.

I have spare relays here if you need any :thumbsup:
 
ive swapd them around, and pulled covers off them and have got them to open and close with eart and a live, one had a little black around the contact point but was still opening and closing
 
Sounds like wiring problem mate, its a pain staking job going from power supply to fan with a multi-meter but its the only way to work out where the fault is
 
yoy were saying that the 3 wires, one is grounde to chassis leg, does the other one become a live when it gets to temp or is it permanently a live when car ignition is switched on? and the othera switch wire, does tis become live, or become an earth when temp switch reaches rite temp?
 
I'll have to double check, think the outside one is constant live the middle becomes live, the black is defo continuity with earth constant.

here the wiring diagram:

radfanwiring.jpg
 
Think depression is starting to kick in, i had another look tis eve and i havnt a problem with wiring going to fans from relays as i got them to work, i dont understand how this works, but i provided an earth to another relay and it kicked in a different relay and sent power down to fan :ponder2:
 
:ponder2: :ponder2: Not sure what ya did and cant picture what ya mean. Where are ya? I wouldn't mind having a look :thumbsup:
 
im in wexford, what i did was, i remove a relay, think it was sub 2? i brought an earth to one of the 4 female spades that relay plugs into, and a a different relay think it main fan 1 clicked and sent power down to fan, it made 2 wires live, one of the wires seemed to light my tester stronger than other,
 
Here's a wiring diagram off a newer model that might be easier to understand:

Radfan.jpg


The only real difference is that the fan motor block connector is a 4pin, but your is 3pin

It shows the earth wire coming from the bottom to the main 2 and sub 2 relay, if you provided an earth the sub 2 relay it was also going to be sent to the main 2 relay and the main fan kicked in, that sounds like a faulty earth from the ecu (probably just a broken wire not a faulty ecu).
 
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