Citroen Xantia heater fan stuck on full speed

[davkirk]

Can anyone help please?? I have a 1997 (r) plate xantia td with aircon,
for some reason as soon as i turn the ignition on the heater fan is stuck on full speed regardless of which position the switch is set.
regards, dave

[KennyW]

Hi Davkirk

See this thread which will lead you onto others!

http://www.frenchcarforum.co.uk/forum/v ... hp?t=18233

Regards

KennyW

[Peter.N.]

You will find the transistors you require on my signature.

[davkirk]

Thanks for the reply kenny, seems a little too complicated for me all that transistor technical talk, at least i have some idea where the fault may be, off to the scrappers i shall go.
regards,

[davkirk]

Thanks peter, much obliged,

[davkirk]

No Luck Folks, I've changed the motor (with a known good one) & it's still the same, i've spoke to an auto-electrician & he says it could be the heater control module under the heater box, i can't find the damn thing, does anyone have any updates?

[davkirk]

[KennyW]

Hi Davkirk,

Could this moderator be underneath the blower.

There is a thread to the offical citroen parts site which you can put details in and you can access the parts diagrams and prices but i can't find it at the moment.
Maybe somebody on the form can give you the correct thread.

Cheers,
KennyW

[davkirk]

hi kenny,
apparently there is a control module near the heater motor with 20-30 wires to it that controls all the heating & air conditioning, apparently they are about £360 (unless the auto electrician is bullshitting me) this car is doing my head in

[Clogzz]

The story of £360 looks highly suspicious.
What does that guy know about something that costs £360 and that we’ve never come across here ?
Where does the ‘known good’ motor come from ?
Have you seen it operate normally with varying speeds on an air-conditioned car ?
This problem is well known, and that’s why you got those good replies so quickly.
Next step is to disconnect the output transistors to see what happens without them.
The fan should be flat-out on the maximum speed setting, and not work at all on all the lower speed settings.

The site for Citroën parts is http://www.citroen-pr.net

[mezuk04]

Davkirk - stick it out!!!!!!

Completely agree with Clogzz, £360 to fix something that pretty much every forum person on here who has owned a Xantia may have pretty much experienced themselves (including myself) and now full well knowing its such a common fault.

Dont hand the cash over and you know never to go back to this dodgy chappie!

[BonceChops]

The control module is sort of between the blower motor and the heating controls. It is mouted vertically almost next to the centre part of the dash. It slides up into a sort of recess in the dash for it. If you follow the thin wires on the blower motor connector you will find it.

[davkirk]

thanks for all the replies folks and "yes" the aut-electrician can cobblers!! i've noticed today that someone has at some time fitted a "jump wire" to fuse 20 .. giving it an ignition live & therefore when i disconnect it & replace it with a 30a fuse nothing happens.. does anyone know where to go from here (also the heated screen stops workingas well when i remove the "jump wire"

[davkirk]

i have found the control module boncechops thank you ... could this be my problem hence the reason the jumpwire has been fitted??

[Clogzz]

The jumper wire to fuse 20 is to bypass the ignition switch contact that went faulty, with the consequence that the blower motor is then supplied even when the key is out.
A good few air-conditioned Xantiae went for wrecking because of dash fires, but I don’t know if this bodgie is the cause of it.
The current for the heater blower is too high for the switch, and there is a modification to supply the blower with a relay:

http://www.frenchcarforum.co.uk/forum/v ... hp?t=17322

This modification assumes that the switch contact is still good to operate the relay, something to check on, since the rear demister no longer works.