Rad fan help - urgent not working

[Purple_rob]

The question is what am I missing to check......

Rad fan is checked and working
Switch is working
fuse is fine
checked local wiring and is fine.

I caught the fan not working in ample time as I know exactly when to expect it to cut in and I always find on a day like this it will be running when I pull up at home.

When I shorted the switch the fan still did not cut in.
Checked local relay connections and swapped a couple around.
When I lived up the back of the altenator the fan worked.

Also to note the perc fan did not work while this was going on and did work while the altenator was lived.

Lastly when I pulled up the second time after my previous stop the fan WAS on but then cut off when I stopped and did not cut in again.

Sounds like a loose connection to me but I cant seem to find it? I beleive the Rad and perc fan relay is seperate???? so I am rulling this out and it has to be a live somewhere along the line.


Any ideas guys as My 5 is my everyday car and it pretty dam hot out lol??

Thanks

[J$£5GTT]

sometimes wiring can appear ok but could be a broken connection inside?

[Yellow]

I went through 2 brand new thermostats from Gsf not long ago and none worked. Which in turn would not let the rad get to temp therefor fan not cutting in. Worth checking if the thormostate is not packed in.

[bigdavec1974]

Has the system airlocked its self?? is the rad getting hot evenly or has it got cold areas??
Might just be 2 unrelated problems, does the perc fan come on when u bridge the thermostatic switch on the heat shield??

[Purple_rob]

I dont understand the 5's wiring enough to grasp this one.

See I live the altenator which kicks in the relay and switch + wiring. Where does this (if constant) live come from.

[Purple_rob]

I've bipassed switch so defo got the system lived and defo no air lock.

[royz]

have you tried a differnt relay as it could be burnt out contacts on the inside of the relay.

[bigdavec1974]

U said u swapped some of the relays around?? they defo all work right?

[bigdavec1974]

After running it for a period, getting up to temp etc turn it off and crack the exspansion bottle open, any excessive pressure?? ie ya bottle spills over the tops??

[Purple_rob]

Bigdave, Not a chance im taking that cap off . There is no doubt that the water will instantly boil as it is under pressure already.

This is defo electric and not water.

I was a mechanic in my previous life so know a thing or two about cars HEHE.

Just cracking out the haynes on wiring.. relay wise I tried to bypass it but could not get the fan to kick in. Tells me theres not a live reaching the relay at all.

[Purple_rob]

appreciate the help here, keep the ideas coming

[royz]

have you got a pice of wire and a 12v bulb handyor a multimeter. as you can use these to see if you have power

[Purple_rob]

yup, got my multimeter out when I was doing it.

I got to teh point I didnt understand the wiring and thought the key was having a live to the alt. I could be wrong...

[bigdavec1974]

Cracking the exspansion bottle after a short run is a sure fire way to check if the system is over pressurised. The water should rise more than 1 inch due to the fact water exspands when hot as you know, it shouldnt shoot out the bottle, if it does, blocked rad, dodgey thermostat, or leaking head gasket/cracked liner. But if u sure its electrical, err cant help, know f all, get all confused
gl mate

[royz]

going of the haynes manual drawing number 22 shows.(blue book)

at the fan relay (item 110) the blak and red wire should go to the alt(item 12).

( this is where the power will be picked up).

the orange wires go to the fan and sensor

with the black at the fan being the earth

hope this helps tracking the fault

[Purple_rob]

Doh!!! I have the green one.

[TNT Tricky Nicky]

From the top of my head, the constant live is fed from the starter motor to the alternator, from there it branches off to temp switch to relay to fan so as long as you have live to alt the problem will be either switch or relay, asyou said fan is working, my money is on the relay.

The perc fan is also wired into that take off although I can't remember how has I ditch the Renault loom and made my own without the perc fan wiring.

My relay worked intermittently making it a pain to diagnose, only a couple of quid so good place to start

[Purple_rob]

I think you hit the key words mate, I'm not sure I have live constant to the alt and thinking it's loose aroung the starter area.

To confirm, the relay is the one next to the rad? Not anything to do with the ones near the perc fan.

As above, the perc fan was not working either. It's got to be a live issue???

[Shane P]

To confirm, the relay is the one next to the rad? Not anything to do with the ones near the perc fan.

The ones next to the anti-perc fan are for the front foglights and the anti-perc fan

[benj88]

Iv just had mine fixd off brigsy tonight, there was a bad connection in the wires connecting to the fan switch, Yesterday my fan wasn't coming on wen it should then wen it did it kept cutting off, jobs sorted could be the same problem mate?

[Purple_rob]

Those ones are nice and clean mate, got the fan to come on when living it a bit further up the loom.

Always when it's the hottest though isn't it lol

[Wallace]

Rob mate if your still having drama's - my work is round the corner from you and theres space to work on the motor...................plus one of our guys is controls engineer (helps me out all the time!)

Buzz me mate if you want to pop round during lunch or after work?!

[Purple_rob]

Cheers mate, got it sorted this morning.

It did turn out to be the loose live at the starter motor.

Problem solved

[Wallace]

Cheers mate, got it sorted this morning.

It did turn out to be the loose live at the starter motor.

Problem solved

Happy Days

[royz]

glad to see you got it sorted

[bigdavec1974]