Xantia 1.9TD 1999

f00lzz · Post by **f00lzz** » 26 Apr 2006, 13:15

With Aircon.

Hi guys

Xantia got a bit hot yesterday, stuck in traffic on M42.. had a look today and the cooling fans weren't coming on even with aircon switched on. Cleaned terminals on three relays between two fans... still no good. I have read through previous posts and subsequently disconnected the plug from the brown connector on the thermostat housing and sure enough both fans start up (initially just one) if I put it back in it stops the fans.
My question is... what is this telling me? Is the brown connector (temp sensor?) knackered or is just to confirm that the fans actually are working and I now need to look elsewhere?

Clogzz · Post by **Clogzz** » 26 Apr 2006, 13:50

Looks like the low speed doesn’t work.
Disconnecting the plug from the brown sensor caused the fans to come on at the high speed.
If only one was spinning initially, it confirms that the other one was faulty.
When one is faulty, the low speed doesn’t work, because they are in series at the low speed.
Since they then both came on with the plug disconnected, the faulty one must have come good for then.
The fault is likely to still be in the relays, or their connections and contacts.
The fan brushes may also wear.
To test for that, with aircon turned on, check for low speed operation.
If nothing, nudge the fans with a stick or something, and if they come on then, it’s a brush fault.
I’ve got a few posts on the subject here, but it looks like I’ve become useless at the search of recently.

The map is here:

http://www.frenchcarforum.co.uk/forum/v ... hp?t=17012

Getting to 11:PM here, back tomorrow.

f00lzz · Post by **f00lzz** » 26 Apr 2006, 16:44

Ok thats interesting info. just to clarify... the second fan caught up after about 3 seconds and since then always cuts in and out together (when disconnecting the sensor plug) I tried the stick in the fan first just in case but no luck ... so, is it the temp sensor that is faulty????

f00lzz · Post by **f00lzz** » 26 Apr 2006, 19:43

If I disconnect the temp sensor so that the fans come on...should the a/c work?

f00lzz · Post by **f00lzz** » 27 Apr 2006, 11:03

Swapped the relays between the two fans today... still no good!

WELSHVIKING · Post by **WELSHVIKING** » 27 Apr 2006, 11:20

Hi, Had the same problem with both my 2000 HDI SX and my 1996 1.9TD SX, both times luckily it was the relays, i simply replaced the 3 relays situated in the triangular unit between both fans and no problems at all after that. I paid £3.19 per relay at my local Motor World shop but im sure you will be able to find a cheaper supplier....Regards Colin

Clogzz · Post by **Clogzz** » 27 Apr 2006, 12:16

If you disconnect the brown sensor, it is normal for both fans to go to the high speed.
When the Bitron fan speed controller senses an open sensor, it goes to emergency mode.
This actually indicates that the brown sensor is good.
As the cooling fan control went to emergency mode; high speed, the air conditioning should not work because eventual aircon faults could add to the emergency.
The so-called ‘left fan relay’ is energised for both low and high speeds.
The 'right fan relay' is energised at the high speed only.
The middle, or ‘change-over relay’ is energised for the high speed, but is still used for the low speed when not energised, through the contact at rest.
So, the fault may still be in the middle relay.
If all 3 relays have 5 pins, they can be swapped all around.
The 2 outer relays are good, because you have the high speed.
Try swapping the centre relay with the ‘right fan relay’.
The ‘right fan relay’ is used for the high speed of the right fan only, and if you take it out to put in the centre, it will just cause the right fan not to work at the high speed, which you don’t need for now.
Simplest may be to do as the Viking suggests, replacing all 3, but my trick will indicate which one is faulty.
And keep us posted.

f00lzz · Post by **f00lzz** » 27 Apr 2006, 12:28

Great... i'll do it afternoon, thanks for the advice guys... appreciated. I just ordered a new temp. sensor from the Stealer so i'd better cancel it then!

Clogzz · Post by **Clogzz** » 27 Apr 2006, 12:37

A quick cancellation will do the Stealer some good.
He should have been able to tell you that it wasn’t that.
I used to get parts for a previous car from an old-school dealer, and when I told him what I was after, sometimes he told me: No, that’s not what you need, it’s this instead.
He was always right, and I never got lumbered with useless parts.

f00lzz · Post by **f00lzz** » 27 Apr 2006, 16:16

Yep he was quite happy to cancel.....and charge me £44+ for 3 relays, still it's only money!!!! And.. if it isn't that then i'll have a play with the Bitron thingy.

f00lzz · Post by **f00lzz** » 28 Apr 2006, 09:47

Changed the relays this morning ...still no good, now to find this 'Bitron Unit' !!

Post by **RichardW** » 28 Apr 2006, 11:35

Hang on a mo before you go ripping half the car apart looking for the Bitron.... think you need to approach it in a bit more scientific manner!

Now... both fans will run at full chat with the brown sensor disconnected. This suggests that the sensor is working, at least in part, and also the Bitron. You have replaced the relays on the fans. But...when you first tried it, one of the fans was reluctant to start. To get low speed the relays connect the fans in SERIES so each sees 6V. If one is U/S then neither will run - it's possible that whilst it will run on 12V it won't on 6V. Assuming that the A/C has gas, then when you switch on, it should start both fans on low, so switch it on and get your multi meter out and see what voltages you have got around the fan relays (fingers out!). If nothing doing, and the A/C won't engage then I'd assume lack of gas and ignore that. So, allow the engine to heat up - the fans on my A/C TD come on low at about 85°C and see what happens to the voltages when the temp comes up - alternatively, it shouldn't be too difficult to run a temp supply off the battery to the appropriate relay to try and get low speed. I'd think that high speed should happen at about 95°C. Don't let it get above 100°C though! You will then establish whether it's a Bitron fault or a fan fault. The Bitron is alleged to hide under the RH headlight somewhere. Maybe.

My money's on the fan....

f00lzz · Post by **f00lzz** » 28 Apr 2006, 11:48

Ok Richard thanks... I have been cleaning contacts on anything that moved this morning just in case, now you have given me something more meaningful to look for i'll give it a go (my electronic skills are v/poor). I did check behind the front headlight.... r/h as you look at the front of car and found this... Oh and the a/c was fine till recently and it does engage and I see green fluid and bubbles in the sight glass

Clogzz · Post by **Clogzz** » 28 Apr 2006, 11:53

The relays would have been cheaper at a parts merchant.
The Bitron itself is rarely faulty.
It’s usually the connecting pins of the Bitron that need a good scrape, and the wiring loom checked for bad contacts.
Looks like you may have to dig up the voltmeter.
I’ve dug up this thread for now, 4 pages, and am exploring for others:

http://www.frenchcarforum.co.uk/forum/v ... hp?t=18058

Edit 10:54 AM: Sorry, Richard, I sent my story before I saw your post.

f00lzz · Post by **f00lzz** » 28 Apr 2006, 12:13

Ah! OK so what I found isn't the Bitron Unit... looks like you need to dismantle the front of the car first to get at it. Going for a blast shortly....when I get the car back together.... and will see what happens.

French Car Forum

Xantia 1.9TD 1999

Xantia 1.9TD 1999

Cooling fans

POSSIBLY RELAYS............MINE WAS