Dismantling The Heater Unit And Fan, repairing fan speed controller

Hi all,

Thought you might find this one useful. Fan speed control often gives trouble and here's how to fix it.

Sorry for the file size but there's lots of pictures to aid explanation.

Cheers

noz

This post has been edited by noz on April 18, 2005 10:31 pm

Hi, Noz,
Thanks a lot for the detailed heater info, I got a blower off a scrapper and found it had had a replacement control module and this was still in good order.
The transistors are marked with a date code, my old ones were 9416 (week 16 of 1994, my replacement was 9644, week 44 of 1996 and were off a 1991 car so the module had been replaced probably in 1997.
Best rgards, ChrisR

Not my day, methinks! Tried to downlad Heater.pdf, got a page-full of hungarian, 85% of it with a line through it.

Tried a second browser, same effect.

Best, T.

Tony

Do you have Adobe Reader? If not then www.adobe.com will provide it free.

Hi,

This is interesting. I have downloaded many of the PDF files on the forum, but recently have run into a problem. Something seems to have changed, as every time I try to download a PDF file I get gibberish. No problem with PDFs from other sites but it seems that each time I click on a link in the forum now it seems to download an index PDF, which appears to be only code. I'm using a Mac.

Any body else having this problem?

Regards
Kiwi

Hi kiwi et al,

I get the same problem sometimes. Its my Norton Internet Security which casues the problem. I just temporarily disable it, download the file and then re-enable it and it works fine. If someone knows how to fix it permanently please let me know.

cheers

noz

I've found no need to disable Norton. Just delete first blank page with X at top RH corner and this will allow access to Adobe to read and print out all 8 pages.

I have a 1992 (K reg) XM 3.0 V6 SEi with air con and climate control and have heater problems.
Fan only works on full speed but all green lights work.
Whatever setting I select it still blows cold.
Seems like the flaps (or whatever they are) to divert airflow are not working.
Car has no water leaks so I would think it is a fault with the control panel.
All help welcome.

Did try to open the file but could not.

Andy

Hi Andy,

If the problem is related to the fan only then the fix is very easy. The file shows you exactly how to fix it. Just right-click on the file and select "Save Target As...". As I said above Norton Internet Security stops me doing it so I just disable it for a short time until the file has downloaded.

If your problem is temperature control then it is possibly the climate control panel on the dash. They are prone to burning out. There are several posts on that subject. Just use the search function at the top right hand corner of the screen to find them.

cheers

noz

Hi all,

First time I've posted on this forum although a long time member on others.
I lived in the UK for 10 years and brought my XM (and a 16V BX) back to Australia when we came home a few years back. This is Cit No. 9.

The photo manual of how to dismantle and repair the heater/AC bits is great.

One question we all would like to know:

Most blower problems come back to the two power transistors which we can replace easily enough.
But, what transistors do we use to replace them?
I've done this exercise a few times now, and used quite a few different types of transistors, as the genuine ones seem to be unobtainable.

None of the replacements work 100% correctly. They either work up to a certain fan speed and then after about 30 seconds cut out, or they only work at lower speeds. Sometimes it will work all day on lower speeds, and then for no reason cut out. I have to then reset the AC controls (digital version) to Auto and it will work for a time but only on low speeds.
Occasionally, I can get ut to run at full speed, but only for a few seconds, before it cuts out again.

So does anyone have a definitive answer to which replacement trannies work 100%, all the time, every time, exactly as the original equipment?

Cheers,

Nodding_dog
1991 V6 SEI Auto
Toowoomba, Qld, Australia

I just tried to download this file and got a page of jibberish also, dont worry, the 'fix' is simple......

Instead of clicking on the link, Right click on the link and choose save as, now type in the correct type of filename, if its called 'super heater repair 101.pdf' dont worry about typing it right, just type 'heater.pdf', its only the last three letters that are important as they tell your computer how to deal with the file, once its saved, you can then find it on your computer, possibly on the desktop, and click it and it will open.

Voila!

obvously if its a picture then you need to make the last three letters .jpg or .gif but you get the idea, dont you.........

I've got a heater blower problem - no blower at all.

Have checked the fuses (OK) - I have no 12v supply at the main feed to the blower. I think I should have? Haynes manual shows a relay between the fuse and the blower but where is it??

Is it the one that's built into the blower motor? if it is, there's no point in stripping the motor out if no supply is reaching that point.

Another thing I have to check is that the live feed is coming from the ignition key contact.....do these fail too, like the xantia?

Any help appreciated.

Hi Wirdy,

Your problem is almost certainly down to the fuse carriers located just in front of the battery tray. The main feed to the blower comes through one of those fuses. They can look OK from above but usually the corrosion gets them from below.

Cheers

noz

Phew, finally downloaded the Heater.pdf file.

FWIW, on a Mac (with only one button on its mouse) I pressed 'Alt' whille clicking on the link. It then dowloaded, calling itself 'index.php.html'.

I changed the name to 'Heater.pdf', and then typed 'Apple-i' to get info about the file, and changed its 'open with' to Acrobat, after first telling the computer to show 'all' applications, not just those it thought suitable.

Thanks, obviously, for doing it. And to Lez for pointing me, finally, down the road..!

Best, T.

Thanks Noz - I'll take a look tomorrow.