Edited by Fluffykins on 08/05/2009 at 14:43

a PNP 10amp transistor from Farnell looks suitable part cope :- 9453130

Paste the link into your browser

uk.farnell.com/multicomp/mj2501/darlington-transis...0

i think the minimum spend on credit card is £20, but they have loads of stuff that will probably save you a lot!!

Hi all,I have this problem (blowers on full, can't turn them off!) with my Citroen Xsara 2.0 HDi 52 plate. I think my problem originates from the fact my alternator diode pack needs replacing - lights bright/dim pulsing!!! Hoping to get the alternator sorted early next week. I think the intermittent high voltage output from the alternator has blown one or more of the power transistors on the blower unit from what I've read here. The reason I'm messaging is just to reassure people and to add info on my experience of how relatively easy it is to get the blower unit out.

All I had to do was use a basic socket set and star key set from Lidl/Aldi's to remove 3 screws to drop the carpet covering under the passenger footwell - NOTE: YOU DO NOT NEED TO REMOVE THE DASHBOARD AT ALL! Once this is pulled aside, there are 3 6mm hex bolts (brass coloured (2 easily visible, 1 towards the rear of the blower unit) - use a screwdriver type socket (you won't get in with a spanner). Also, just for those that don't know, the blower unit takes up a large area under the dashboard here (a good 6"+ across) - ie it's staring you in the face :) . Towards the back there is a plastic clip of sorts as part of the blower unit that you need to open by hand and release a loom of multicoloured wires (this loom is not going to the blower unit, just annoyingly passes in front of it), and at the front you need to remove a single wire connector, and a 4-wire connector (this doesn't have a release pin, it's just very stiff!). The gently pull off the 1/2" rubber hose that is attached to the blower drain port at the lower back. Pull the loom of wires from the back towards you and drop the back of the blower unit down and the whole unit will drop out into your hand.

Now with the blower unit on some paper... There are a couple of 6 mm hex bolts holding the PCB in place. Then turn the whole unit over and remove the phillips screw from the housing and the cover will come off (you'll need to remove the wire loom by the way).

To remove the transistors (big 1" jobbies!) I used a cordless drill with a 5mm drill bit to kill the rivets on the transistor side (not the PCB side) and then, if the rivets didn't fall out, finish with a 3.2mm drill bit. To remove the transistors, you'll need a soldering iron that's either good at maintaining a temp of around 350 or if you're like me and it cost £25 from Farnell, just put it higher and do it quick! Solder suck out the solder from the two pins on each transistor while pulling the transistor(s) free. My PCB was held in place by 2 locating posts (1 at each end of the PCB) that it was pressed onto - using a flat blade screwdriver you can lift the PCB off these but there is no real need. All I need to do now is get me some replacement transistors.

I think it's worth replacing both transistors for all the effort here and, to be honest, if one has blown due to a voltage spike, the other has probably been stressed and could blow any time!

Will repost on here if this sorts my problem out.

Cheers

Jimbo

Edited by JimboStlawrence on 30/07/2011 at 18:50

Here is a data sheet for the PNP transistor required www.onsemi.com/pub/Collateral/MJ11012-D.PDF

It has to handle up to 30A so there won't be many alternatives.

Alternatives alltransistors.com/transistor.php?transistor=40350

There are plenty available through eBay www.ebay.co.uk/sch/i.html?_from=R40&_sacat=0&a...5

but some suppliers won't post things to Africa.

Maybee you know someone in Europe who could order it then forward to Africa & keep fingers crossed it arrives.

hi there, i have the same problem but on a citroen c3 2002 i was wondering would it be the same on a c3 as described in here as i have looked all over for a solution and this is the closest ive come to finding a solution.heres hoping.

I also want to thank the posters for their advice.

It drove me mad for 3 years and then following the instructions I swopped the 2 power transistors with similar ones and it worked perfectly.

I actually had the garage remove it as the screws are box heads but I then replaced it with normal Philips screws.

Don't forget to reconnect the aircon drain pipe if you have one.

A few posters asked if other issues could be the same problem.

I found over the 3 years that sometimes the fan would work on full on all settings and sometimes just on the highest settings. Changing the transistors solved all the issues.

Be careful to mark the heavy lucar connectors before removing otherwise the fan will go backwards. Actually it's a good idea to photo the set up before you start.