Xantia radiator/cooling fans

romie · Post by **romie** » 20 Apr 2011, 13:42

After reading all the bits on here, I've found I have 3.5ohms across one fan but not the other. Please see picture for where the open circuit is.

So the problem lies between that terminal 5 contact, (where the relay sits) and the battery earth.
So it's an open circuit between 'fan-and-earth' or 'fan-and-relayboard' or 'both'... meaning broken/corroded wires, motor brushes or open circuit on the fan motor.

My question is this: Is there a simple way to get-at or diagnose this without having to pull the front bumper and fan assemblies off? or 'from experience', 'I might as well just get on with it'?

Cheers

romie · Post by **romie** » 20 Apr 2011, 13:44

ok slight mistake, so that red arrow to earth should really be pointing to the battery earth as I don't know where the fan earth is - Probably behind a few hours of crawling under the car

citroenxm · Post by **citroenxm** » 20 Apr 2011, 15:02

Fan Earths are bolted to the inner wing to the RIGHT of the battery...

They are the large green wires for ease of ID..

Firstly, have you checked the Relays between the Fans behind the grill?? These are common for corosion of the relay terminals...

Paul

romie · Post by **romie** » 20 Apr 2011, 15:52

Heya, ah nice one. Thanks for that info!! Is kinda what am after

But I suppose if after inspection of these joints I'm still left with an open cct then I'll just have to pull the damn things off to get hold of the motor windings/brushes directly ~ sigh.

Symptoms:
Both fans don't run.

Testing:
Yeah, I've got to the point of disconnecting the brown connector on the thermostat housing, (causing the ecu to switch the relays over so both fans should be wired in parallel to the battery and so should be at 'full speed') then pulling the grill off exposing the relays and going through the wiring diagram as shown in the above picture.

So when I pull the brown connector off, nothing happens for three seconds then the off-side, (right as seen from the drivers seat), fan kicks in at 'full speed'.

All three relays can be heard to switch over when inserted into their relevant sockets.

There is +12v on both the fans relays pin3.

With the change over relay inserted I get 3.5ohms between pin5 on the fan relay and battery earth - as to be expected. But on the other relay between pin5 and earth I get nothing.

An interesting point here is that my fan relays or fans, seem to be swapped over on my vehicle as opposed to what's described in this link first picture: http://www.peugeotlogic.com/workshop/ws ... fanop1.htm
Each fan is controlled by the 'fan relay' closest to it. Not the other way around as shown in the first image.

I need to get to the backs of the fans really to just either apply 12v directly to the windings, measure their resistance or check the brushes. I'm just not fancying having to strip the car down to do it :/

I've seen on here that the fans CAN be taken apart and their bushes replaced. Any idea where I can get these bushes? alan s said they were 4 brushes each 6mm X 8mm and approx 18mm long. See link.
http://www.frenchcarforum.co.uk/forum/v ... hp?t=10752

Cheers

romie · Post by **romie** » 20 Apr 2011, 15:56

spose I should check that the 12V actually gets passed across to pin5 with the relays plugged in. . I'll do that tonight by shoving the probes in at an angle :/
But they look good and I can hear them all operating cleanly. . not suspecting this but will check.

AndersDK · Post by **AndersDK** » 20 Apr 2011, 16:51

Have you checked the fan itself ?

If this read hi ohm you instantly know.
If not - its either the relay, relay socket or associated wiring.

The fans are known to get defective.

romie · Post by **romie** » 20 Apr 2011, 16:59

Hi AndersDK, well this is the whole point of this topic.

I'm trying to avoid having to pull the car apart but it's looking a lot more likely that I'm having to do it to get to the fans windings.

If it turns out to be the bushes then I don't suppose you know where to get hold of replacement bushes do you? I bet the fans are not a 'serviceable part' in Citroens' eyes :/

MikeT · Post by **MikeT** » 20 Apr 2011, 17:07

Is my thread any help to you? It lists what should be found at certain pins on my MK2

http://www.frenchcarforum.co.uk/forum/v ... ns&start=0

The resolution, if you find yours has the same diagnosis, can be found here

http://www.frenchcarforum.co.uk/forum/v ... &start=120

Clogzz · Post by **Clogzz** » 20 Apr 2011, 17:33

Each fan is controlled by the 'fan relay' closest to it. Not the other way around as shown in the first image.

Yes, the pictures are from the Peugeot 306, where the top relays are the ‘wrong’ way around.

AndersDK · Post by **AndersDK** » 20 Apr 2011, 17:39

Use a jumper wire to shortcircuit the relay contact set pins in the relay socket.
That will at least tell you if the wiring & fan is working.

Then you instantly know if it is a control or power feed problem.

romie · Post by **romie** » 21 Apr 2011, 09:01

MikeT wrote:Is my thread any help to you?. .

Thanks, I've already been reading these posts which have helped a lot

As the open circuit is between the three relay housings, fan and the fans earth I think the problem is going to be very local to around the fan itself.. possibly its earth

Think am just going to have to find a spare day, pull up a few beers and just pull that damn bumper off - sigh.

Clogzz wrote:Yes, the pictures are from the Peugeot 306, where the top relays are the ‘wrong’ way around.

Fantastic, thanks for confirming that. I can stop double checking that and move on. Cheers.

AndersDK wrote:Use a jumper wire to shortcircuit the relay contact set pins in the relay socket.
That will at least tell you if the wiring & fan is working.

Then you instantly know if it is a control or power feed problem.

Cool, yeah. I'll do that then I'll just get on with pulling the front off the car. (Can you tell I'm not enthusiastic about this?)

Oh, the cars done 196000 miles now so it's prob just bits wearing out, anyone thought of where I can get replacement brushes for these fans? (see above for measurements)

Cheers guys

Post by **KennyW** » 21 Apr 2011, 09:58

Romie,

When my Xantia had fan problem it was a bad connector leading into the fans at one of many connecotrs.

The bad news was i had to strip the front of the car to access it all.

your problem is slightly different from mine because when i pulled the brown plug both fans operated at high speed.

As Anders suggest supply both fans with a live feed and you will find out if both are working and if you bridge the relays you will also be able to confirm you are getting a live feed from the battery.

Kenny

romie · Post by **romie** » 21 Apr 2011, 11:36

Cool, yeah am going to definitely do that. Oh, but thinking about it, as I've got an open circuit from the input to the +ve supply to the fan in the relay housing and earth, there is no point supplying a 12V feed as there is nothing for it to drive :/ -> totally open circuit. . sigh.

Cheers for the thoughts!

romie · Post by **romie** » 21 Apr 2011, 13:37

Hey, so after looking at the circuit diagram I should be able to just remove the 40A fuse from the non working fan and link pins 4 and 5 on the change over relay and at least have one fan running (be it at full speed) in the meantime.

This should stop car from totally cooking for now :/

Clogzz · Post by **Clogzz** » 21 Apr 2011, 16:25

The working driver’s side fan is switched by the driver’s side relay, so won’t spin by linking change-over socket connectors.
Try tapping the faulty motor with a hammer or mallet to ‘reseat’ the brushes.
If the faulty motor spins more freely by hand than the good one, it’s because it has less friction from the brushes.
Replacing brushes is too much trouble when you can find good motors from wrecks.