Heater Fan Speed

zzf00l · Unread post by **zzf00l** » 23 Jun 2005, 11:27

Year 2000 Xantia 3.0
Hi. I have a problem with the fan speed on my heater/aircon. No matter where I set the fan speed controller i.e Auto/Max/Off etc the fan still operates at Maximum speed. Not too much of a problem during this hot spell but it certainly is noisy. Any ideas where too start looking?

Unread post by **martyhopkirk** » 23 Jun 2005, 17:08

Resistor pack seems a likley suspect. On the other hand - try giving the little air con sensor fan next to the clock a blast out with some compressed air (if you can, remove, clean and lube it)it may be sending false messages to the control - though shouldnt think its this stranger things have been known with Xants...

Unread post by **Peter.N.** » 23 Jun 2005, 18:34

If it's got 'auto, it must have a transistor controlled blower as in the XM. It could be that one or both of the transistors on the motor have gone s/c, alternativly, it could be the temp control unit, but I would go for the motor first.

zzf00l · Unread post by **zzf00l** » 24 Jun 2005, 01:14

Cheers guys i'll check it out this weekend

guillermo · Unread post by **guillermo** » 24 Jun 2005, 01:21

100% it is one or two transistor of the controller.
Regards
Guillermo

zzf00l · Unread post by **zzf00l** » 03 Jul 2005, 16:34

OK guys.
Removed the motor and of course it looks nothing like the motor shown in my trusty Haynes Manual...this is the 'facelift' 1.9td of year 2000 vintage. Have removed what looks like some sort of transistor pack attached to a PCB and if I can work out how to get some pics on here I will do so!

AndersDK · Unread post by **AndersDK** » 03 Jul 2005, 18:54

To put pictures here :
http://www.andyspares.com/discussionfor ... IC_ID=8459

zzf00l · Unread post by **zzf00l** » 03 Jul 2005, 23:26

Here goes nothing!

zzf00l · Unread post by **zzf00l** » 03 Jul 2005, 23:27

Cheers Anders.
Now.... can you help me????

[email protected] · Unread post by **[email protected]** » 24 Jul 2005, 05:03

hi zzfool
i have the same exactly the same problem with my xantia have you managed to cure it yet let me know ive also had those transistor packs out of mine two so i reconise them well. also you dont live far from me
pete..........................

Mandrake · Unread post by **Mandrake** » 24 Jul 2005, 06:49

Has anyone else ever had a problem with intermitant fan speed control ? On more than one occasion on my Dad's 1994 SX and once (so far) on my 1997 VSX I've noticed a situation where the fan speed control is inoperative -
When it happened, the air conditioning was turned off (both cars have air conditioning and include an "Auto" setting on the control) and the fan was running, and then when I go to adjust the fan it won't change speed. It will be locked on whatever speed it was previously on, regardless of sliding the switch anywhere, even triggering the A/C on then off wont have an effect.
When this happened to my car for the first time yesterday I pulled off the road and fiddled with the controls to no avail. On a hunch I then turned off the ignition and turned it back on - Voila, fan speed control now responds again, all settings including auto working properly.
It seems almost as if there is a small computer that controls the fan speed, (possibly in combination with the air conditioning system especially when set to auto) and that this computer on rare occasions might "crash" leaving the fan stuck at whatever speed it was running at. Turning the key off and on must reset this controller.
There must be *some* kind of electronic controller involved in controlling the fan speed (whether just a simple electronic one, or a small computer) as (a) there is a significant delay between moving the switch and the fan speed changing, and (b) the functioning of the Auto position in tandem with the A/C.
It's probably happened on my Dad's car about 4 times in the 4 months he's had it, and happened once on mine and I've only had it a week [:D]
Anyone got any ideas ? I would have thought if it was a faulty transistor pack the fan would be permanently on, but that is not the case, after turning the ignition off and on it is back to normal again...
Regards,
Simon

Clogzz · Unread post by **Clogzz** » 24 Jul 2005, 17:49

http://www.andyspares.com/discussionfor ... erms=relay
Have had that problem.
The current for the heater goes through the ignition switch that can't cope with 30Amp at high speed.
The electronics under the fan get reduced voltage and they lose reference to control the speed.
The reduced voltage also causes lack of current for high speed operation.
Mine would cause total loss of speed control.
I couldn't turn the fan off...it kept spinning at reduced speed on all settings, even 'off'.
I got given a hand-drawn diagram showing the ignition switch operating a relay that took the fan supply before the ignition switch and went to the fan through a 35Amp in-line fuse.
I got told very clearly that the diagram had to be ripped up when the job was done, and I duly did that.
This job involves the removal of the steering wheel and shrouds.
I broke the top shroud mounting in the process, and glued it back in.
I made a small hole in the top shroud to insert a screwdriver to reach the top mounting screw for next time I have to go there.
It is impossible to loosen the top screw without seeing it.

zzf00l · Unread post by **zzf00l** » 25 Jul 2005, 11:21

Different problem I think.....If the transistors are faulty the fan speed gets stuck at MAX speed because this is the only speed not controlled by the transistors.
If the Ign. Switch is faulty I believe it can be completely inoperative or stuck at any speed between OFF and MAX...(I think).
Ian

Clogzz · Unread post by **Clogzz** » 25 Jul 2005, 18:30

<blockquote id="quote"><font size="1" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote"><i>Originally posted by zzf00l</i>

Different problem I think.....If the Ign. Switch is faulty I believe it can be completely inoperative or stuck at any speed between OFF and MAX...(I think).
Ian
<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">
Yes, different fault.
Was in reply to Mandrake's post.