Xantia 1.9TD 1999

Clogzz · Unread post by **Clogzz** » 29 Apr 2006, 10:57

Why do they have all these differences and variations and modifications ?
It looks like they are running a cottage industry.
Try turning the aircon on with only one green relay plugged in.
If you hear it click on, then that’s the ‘left fan relay’, for the left fan as seen from the driver’s seat, but opposite as seen from the front of the car.
If it doesn’t click on, then it’s the ‘right fan relay’, used for the high speed only, and not needed for this test.
I don’t think that electrics will defeat you.
If I remember correctly, you have posts about changing valves and camshafts.
This relay exercise is just wire pulling compared to that.

f00lzz · Unread post by **f00lzz** » 29 Apr 2006, 22:23

Have been out (in the V6) today just got back in 22:22 will have a go at your suggestion in the morning (Sunday a.m) thanks for staying with the topic...appreciated.

Clogzz · Unread post by **Clogzz** » 30 Apr 2006, 11:10

Good to see that you intend persevering with it.
If you don’t feel like going through the testing rigmarole, then checking the plug/socket to the fan that was slow to start may pay off.
It may just need a good squirt of Holy Water.
Apart from that, there’s still the fan brushes that may be worn.
The stealers sell new fans for big bikkies.
There is a fan repair topic written by alan s, and I’ll dig up if required.
Have a good fiddle !

f00lzz · Unread post by **f00lzz** » 30 Apr 2006, 11:24

Hi.. A few jobs to pacify the Wife then i'm off too play with my cars $\:D/$

f00lzz · Unread post by **f00lzz** » 30 Apr 2006, 11:29

Just thought.. do you think it likely that the Bitron Unit may be the cause? Is it worth stripping the front off the Xant to get at it???

Dave Burns · Unread post by **Dave Burns** » 30 Apr 2006, 11:40

There may well be a problem with the relays but the main problem sounds like it is with the brown bitron temperature sensor.

If when you pull the plug on it the fans come on, and yet they are not energised by engine over temperature, this may be indicative of the sensors inability to change resistance with rising temperature.

Get a good multi meter and check the resistance of the sensor when cold, then check it again at normal engine temp.

Are you sure only one fan came on initialy when the bitron plug was pulled, if you were going just be ear do it again and look at them, both should fire up in low speed and a few seconds later both should go to max speed.

There was a thread a year or two ago which gives the resistance values at which the fans will energise for both stages, if you can get hold of a resistance box you can check the operation against those values.

Dave

Clogzz · Unread post by **Clogzz** » 30 Apr 2006, 11:58

Wasn’t suspecting the Bitron or brown temperature sensor because I wouldn’t expect them to cause one fan to come on first, and the other one next.
Dismantling the front is a last resort, for when it’s established that the Bitron is at fault.
I've had Bitron troubles, but a good scrape of its connecting pins fixed it.
On my car, the Bitron is in the fuse box under the bonnet, and was a minor job.

f00lzz · Unread post by **f00lzz** » 30 Apr 2006, 12:52

Dave Burns wrote:There may well be a problem with the relays but the main problem sounds like it is with the brown bitron temperature sensor.

Cheers for the input Dave.. I have changed the Relays (3) If I had to choose between spending £18.50 for a new temp. sensor and locating the 'Bitron Unit' behind the headlight I would go for the sensor unit... any views on that?

Please Guys don't make too much of this 'one fan coming on first' it really was only a few seconds and hasn't occured since.

Keep going with the ideas... it doesnt matter to me if it turns out wrong... it's the principle of avoiding the Dealership

Clogzz · Unread post by **Clogzz** » 30 Apr 2006, 13:07

The only way I know to check on that is as per Dave’s post.
You would need at least a resistor of about 1,000 Ohms to check on that, by disconnecting the sensor wire, and bridge the wires with the resistor.
Otherwise, it might be worth trying to short the sensor wires, so they don’t sense anything, and won’t send the fans to the high speed.
Doesn’t look like your fault is lack of high speed at over temperature, because they don’t come on at the low speed with the aircon.

Edit to change 'resisitor' to 'resistor'.

f00lzz · Unread post by **f00lzz** » 30 Apr 2006, 13:12

OK thanks, as soon as I have done enough housework for the wifey to let me out too play.... i'll crack on.

Clogzz · Unread post by **Clogzz** » 30 Apr 2006, 13:34

Looking at the map …
All relays out first, then aircon turned on, push a green relay in a 4-pin socket just enough to feel and hear if it clicks on.
It should click on only in the ‘left fan relay’ socket.
If it does so, then the ‘left fan relay’ socket is also identified.
The 5-pin ‘change-over’ and the other relay should not click on.
If that’s how it goes, then the brown sensor and the Bitron are out of contention.
That’s because at the low speed, only the ‘left fan relay’ is energised.

f00lzz · Unread post by **f00lzz** » 30 Apr 2006, 14:20

OK i'll try it. thanks

Clogzz · Unread post by **Clogzz** » 30 Apr 2006, 17:15

Time to

If there are still problems, next to try is to connect both fans in series directly to the battery, to see if they both spin at the low speed when the relays and wiring are disconnected from the fans.
The fans will have a piece of wire with a plug and connector going to the relay box.
With the brown plug disconnected to spin the fans at the high speed, work out which wire is 12 Volts positive on the fan plugs.
That’s to prevent applying the wrong polarity, and reverse spin of the fans.
Well-used motor brushes may not like reverse spin.
Connect one fan positive wire to the battery positive terminal, and the negative wire of that fan to the positive wire of the second fan.
The negative of the second fan goes to earth.
The fans are then in series, and must spin at the low speed.
If not, the fault can only be in a fan, or its wire and connector.
If nothing spins, and the fan that’s got its positive wire connected to the battery has 12 Volts on both wires, then that’s the good fan.
If it has 12 Volts on the wire to the battery, and nothing, or low voltage on the wire to the other fan, then it’s the faulty fan, meaning the fan with its positive wire to the battery.

Back tomorrow.

Edit Monday 12:04 PM ... No news, good news ?

Dave Burns · Unread post by **Dave Burns** » 01 May 2006, 21:03

This is the old topic that contains the resistance values for the bitron sender unit.

http://www.frenchcarforum.co.uk/forum/v ... 42&start=0

Dave

f00lzz · Unread post by **f00lzz** » 01 May 2006, 23:25

Cheers...all usefull info. gratefully received.