HELP!! Xantia Cooling Fans Driving me nuts!!

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ecohouse1
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HELP!! Xantia Cooling Fans Driving me nuts!!

Post by ecohouse1 »

My Radiator Cooling Fan issue is driving me beserk and really getting me down. I have looked at all the obvious things but maybe I have missed something so any pointers welcome!

Symptoms:

Radiator cooling fans come on pretty much all the time now, but still intermittent and random. Mostly on starts - cold start - turn key - before even the glow plug light goes out, the fans start up. Half speed for 1-2 seconds then on full tilt! They then stay on the whole journey, regardless of engine temp, although sometime they come on a minute or two after start, then shut down after a mile or two. Mostly now on for the whole journey whether 30 minutes or 3 hours! Full tilt!

ACTIONS SO FAR

Replaced Brown Thermistor sensor and cleaned contacts. No improvment
Swapped out Bitron unit under N/S headlamp- cleaned contacts. I used a Pug 206 1.9 D Bitron - ran the same apart from being 5 degrees hotter. Original Bitron now back in situ
Changed all the Fan relays over - Strangely I get a small improvement after removing the fan relays and replacing them, but almost on the dot of 2 days later - full tilt fans from start again.
Removed Outer Wing N/S to check that I did not damage the wiring when I welded the door pillar - all seems fine.
Checked all multiplug connectors in the vicinity of the battery tray and cleaned - no improvement.
Cleaned up the earth connections to the inner wing next to the battery.

With the slight improvement on fiddling about with the relays, I am wondering if it could be linked to bad connectors at the back of the relay unit in the fan housing? I presume I have to remove the fans unit to access this?

I have also checked the wiring to the Bitron and the connections from the brown thermistor to the correct pins in the bitron multi plug are good with little resistance. Ditto the Multiplug to the relay contacts checked oK.

From reading the very informative document from a previosu posted of a Pug 306 cooling fan systems it appears that the Bitron unit completes circuits to earth to operate make the fan motors run, so I am assuming that there is a fault to earth somewhere?

Can anyone point me in a new direction of enquiry or any well known trouble spot I could focus on?

Has anyone run a mod on the system to return the fans to a simple thermo switch & relay circuit? I am almost at that point now?

Any help greatfully received!!!!
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Re: HELP!! Xantia Cooling Fans Driving me nuts!!

Post by RichardW »

Have you had it on a Lexia? This may give a pointer as to what the ECU is seeing. It could be a fault with the AC pressure sensor for instance. The other place to look is the wiring duct along the bottom of the rad (bumper off) - wires are prone to rotting in here, and this can lead to all sorts of oddities.
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Re: HELP!! Xantia Cooling Fans Driving me nuts!!

Post by ecohouse1 »

Thanks Richard, I wasn't sure if the Lexia would work on Aircon and cooling issues. I might give that a bash. One of the other posters, Chris has one and kindly offered it to me if I needed it so will take him up on it. The wiring loom under the radiator, is that the large 1.5 " wide one in the corrugated black plastic tube that clips on to the underneath of the radiator cross member?, or is there another one inside the bumber itself? I had (Admittedly a quick peak) look inside the big corrugated one and all looked k but I did not completely disgorge all the wires for closer inspection.
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Re: HELP!! Xantia Cooling Fans Driving me nuts!!

Post by DickieG »

Is the heater airflow direction lever directing air towards the windscreen? If so then it turns on the A/C which also turns on the cooling fans.
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Re: HELP!! Xantia Cooling Fans Driving me nuts!!

Post by VertVega »

It seems that you've done almost "all" with the radiator cooling fans.
So I would suggest to check one more minor item which might have effect on this case.

In my previous car Xantia 2.0i 16V petrol there were 3 temperature sensors (Green, Blue, Brown) in the thermostat housing. One of them sends temperature reading to the air conditioning system. If the sensor is defective and the data is wrong (ex. too hot) then it might force the fans run on high speed.

This is just an idea. It might be worth checking.

--------------

If the radiator fans are under heavy usage the motor brushes keep getting shorter and by the time you might need to replace the fan motors.

This thread in Handy Hints & Tips might be useful --> Xantia II - Radiator fan motor removal

---------------
Edit:
I found a pic. which I sent for another subject. Temperature sensors are seen.
Xantia MK2 petrol thermostat housing

Image

BLUE - SENSOR ENGINE - INFO WATER TEMPERATURE FOR DISPLAY
MAROON (Brown) - SENSOR - INFO ON CENTRAL TEMP CONTROL HOUSING
GREEN - There is just a plug if the car is without air conditioning. So you should check this sensor. It might be open-circuit or broken wire and providing false data of the coolant temperature.
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Re: HELP!! Xantia Cooling Fans Driving me nuts!!

Post by ecohouse1 »

Thanks Vert Vega - my 1.9 TD only has two sensors - Brown for the Fans ECU and Blue to the dash temp guage. I don't appear to have a green one.
I have continuity tested the connections from the brown sensor to the relevant pin inputs on the Bitron and they are fine plus the resistance between the plug and bitron is negligible. Tried a new sensor too and no change :(

Just a thought, does anyone know if low refridgerant can give these symptoms? The system blows out barely cool air so I am assuming the system is almost empty and there are lots of bubbles in the sight glass. Would this mae any difference to fan function.

As regards the vent control lever in the dash, the fans operate on all positions of the switch even face vents and floor.

I had a look at the wiring loom under the radiator last night and poked about the wires and they all looked in remarkably good condition. I also started the engine along with the accompanying fan howl and manipulated the wires around and all the relays in the housing (tricky business trying not to lose digits mms away from spining fan blades! :lol: ) None of the manipulationsa made any differnce to the fans. Beginning to think its the air con switch? Is that the silver circular thing on the dryer with the plug lead attached? I unplugged this while the engine & fans were running and there was no difference, would this indicate anything?

I must admit electrical stuff is not my strong point!

Chris Morewood is kindly letting me hook up his Lexia to my car (its never had a diagnostic before- so god knows what else will show up!!)so maybe early next week I will get an insight to any logged faults.

I was thinking of recharging the air con anyway soon, and wondered if the issues could be connected?
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Re: HELP!! Xantia Cooling Fans Driving me nuts!!

Post by VertVega »

ecohouse1 wrote:... Just a thought, does anyone know if low refridgerant can give these symptoms? ...
Low refridgerant would not cause this but it causes a very loud compressor.

In my Xantia with low refr. I was able to clearly hear in the cabin while driving when the air conditioning compressor clutch was engaged and the compressor was "working". Of course the bubles also give the message :)
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Re: HELP!! Xantia Cooling Fans Driving me nuts!!

Post by CitroJim »

Although you checked the continuity of the Bitron (brown) sensor wiring back to the ECU, have you tried flexing the wires? It sounds like it may all be a bit intermittent there...

It's a failsafe that if the Bitron goes open-circuit the fans will run at full speed. It's always a good fan test to disconnect the Bitron and see they do..

If no indeterminacy can be found in the wiring then I'd be temped to swap the ECU...
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Re: HELP!! Xantia Cooling Fans Driving me nuts!!

Post by Clogzz »

the resistance between the plug and bitron is negligible
So was mine, somehow.
One of the wires had 0.2 Ohms and the other one 3.7 Ω.
That was a faulty crimp in the plug going through the inner wing.
I ran a new wire around the connector and that fixed it for good.
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Re: HELP!! Xantia Cooling Fans Driving me nuts!!

Post by ecohouse1 »

Thanks, Jim I have swapped around the ECU Bitron unit with a 2nd hand Pug 206 D one and no difference unfortunately. I did try "wiggling" the wires from the brown sensor to the loom (2 wires) but again no difference.Clogzz - where do the wires go at the inner wing? Is that the light grey plug in connector attached to the inner wing with three wires? I have disconnected this and cleaned the contacts as well as manipulating it while the fans are on and there was no difference.

I had the outher N/S wing off in March to weld the A pillar hinges and cleaned up the inner wing and slapped some POR 15 on - 2 weeks after the fans started on cold starts, my initial thought was they were related but when I took the wing off again 2 weeks ago the wiring looked OK. I did see a big moulded clear plastic plug that seems to carry wires through the wing but it looks compeletely impenetrable so I am assuming that this free from any blame?

After the brown sensor on the thermostat the wires run down into the loom above the gearbox - I don't actually know where they go after that! But is you can point out where they reappear near the inner wing that would be great. Although as I said I tested the pins on the bitron connector that link to the thermister and the resistance seemed OK. Will test again though.

Going over to see Chris on Monday to plug in the Lexia and see if that shows anything.

If it doesn't, I am even thinking about using the, now, permanent live supply to the fans as a the feed to an extra Relay, controlled by another thermistor (Temp guage one?)to operate the fans only above 95/100 degrees.

Its a shame as in all other respects the car is great and its the kind of fault that grinds you down and gets you hacked off with the car. :(
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Re: HELP!! Xantia Cooling Fans Driving me nuts!!

Post by ecohouse1 »

Something like this even:

http://www.ebay.co.uk/itm/AeroLine-Capi ... 1054632193" onclick="window.open(this.href);return false;

As it appears that I could fit it to the top hose? (would have to exit at the thermostat end though due to the bayonet at the other end! Controlling a relay fed from the existing feed, so leaving the whole Bitron system untouched as I know it interfaces with the air con etc. As the fans are energised permanently now, at least the actual fans would only run when I set the temperature at a predetermined level, and switch off again. Also if by some miracle the system "self repairs" it would just be a belt & braces.

Just a thought to restore my sanity!!!
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Re: HELP!! Xantia Cooling Fans Driving me nuts!!

Post by CitroJim »

Eco, to help you resolve this, I can provide full wiring and harness diagrams for you..

What model exactly?
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Re: HELP!! Xantia Cooling Fans Driving me nuts!!

Post by Clogzz »

where do the wires go at the inner wing?
Through a connector with about a dozen wires, just behind the battery.
That was on my 1995 petrol Xantia.
The brown sensor wires were passing through there.
The connector had a coloured sliding latch to pull upwards for opening it; but I can’t remember what colour.
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Re: HELP!! Xantia Cooling Fans Driving me nuts!!

Post by ecohouse1 »

Thanks Jim, its a 1.9 TD - T plate 1999 SX model estate Cheers
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Re: HELP!! Xantia Cooling Fans Driving me nuts!!

Post by CitroJim »

ecohouse1 wrote:Thanks Jim, its a 1.9 TD - T plate 1999 SX model estate Cheers
OK, perfect... I'll see what I can dig out...
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