biggeeeee · Jun 20, 2012

Had a fault with the blower in my Discovery II last year and tried all sorts to fix it. Fault being the blower only worked on position 4 or not at all.
I replaced the Climate Control Panel with no effect, I thereafter changed the complete blower motor from an 03 plate Discovery with no joy.

The original story is here -

http://www.landyzone.co.uk/lz/f8/blower-heater-cheap-fix-128192.html

Eventually replaced the resistor pack, managed to pick up a new one on Ebay for £50.

Even more expensive (£108) to replace from a dealer :
JGN100010 AIR CON BLOWER TRANSISTOR | Discovery 2 1998-2004: Electrical | shop | www.lrseries.com | L. R. Series

I had toyed with the idea of attempting to replace the transistor only but couldn't find one, fannied about for a while and eventually did find one and replaced it, took photos of the fix and then put the unit on a shelf and forgot about it.
Found it today and tested it in the Disco and hey presto it works.
So for a cheap fix here's how I did it

Firstly you need to remove the Glove Box lid,
For some reason RAVE have the resistor pack on the right hand side, its on the right hand side, with the lid removed there is one screw holding the pack on, remove this and the pack will come away from the blower motor, disconnect the multi-plug and remove the resistor pack.

With the pack on the bench remove the screws holding on the plastic cover,
You now need to Desolder the two connections circled to release the transistor and also undo the two bolts holding it to the heat sink.

With the transistor removed the pack will come apart and you should have the following

replace the transistor

and rebuild the pack, solder the transistor in place(it only fits one way) bolt it to the heat sink and replace the plastic cover.

Refit the pack to the blower motor and hopefully you should now have a working blower.

I managed to pick up the transistor via an internet search, it cost £8.50 delivered. The company I bought it from have no more stock, there are some listed on Ebay but all from the States.

It took me around 20 minutes to replace the faulty part.
All in all a good fix which should save you the best part of £100

Hope this helps

HenryD · Jun 21, 2012

nice one.

myjosef14 · Sep 18, 2013

Great post.

followed these instructions and did the repair myself, ordered the part on ebay from the states for £10.

thanks for the help

myjosef14 · Sep 18, 2013

well it worked for 5 mins? then back to normal.

myjosef14 · Sep 19, 2013

may of over heated the last one with my crap soldering! however a electrical engineering friend of mine found this pattern part at RS.
Buy Darlington Transistors Trans Darlington NPN 400V 15A TO-3 STMicroelectronics BU941 online from RS for next day delivery.
£2.78, bought two in the end, quick phone call and made an account with them, will be delivered tomorrow for free!

well happy, just hope it works when my soldering expert friend sorts it out on saturday, ill keep you posted.

myjosef14 · Sep 20, 2013

Transistor arrived this morning, took my time this time with the soldering being careful not to over heat it.

Job done, all working again, very cheap fix £6.67 for 2 (one spare)

happy again.

Now onto the leaky sunroofs!!!

brianconwy · Dec 13, 2014

So thankful for this thread. Took our 03 disco 2 to a local mechanic about 7 years ago and he had no luck. Didn't want to pay main dealer prices so we just lived with the problem since.

The only place I could find the BU941 was abroad so I have used MJ11016 and it seems to have fixed the problem. £3.28 including postage.

Thanks all.

biggeeeee · Dec 13, 2014

Over two years later and I still have the repaired one sitting in the garage!

ClassikFan · Jan 24, 2015

My heater only works on setting 3 - 4. Is this the same issue?

sierrafery · Jan 24, 2015

if it's not the digital aircon control but the manual type it's not the same, the issue presented here is about the blower speed no matter if it's heater or aircon, the classic type doesnt have that tranzistor but a rezistor pack and that might be your problem

ClassikFan · Jan 27, 2015

Having had a search on here it seems that the resistor pack problem shows as the fan only working at full speed. Mine does nothing on 1 or 2 but works on 3 & 4 so what is the likely hood that the resistor pack is the problem?

sierrafery · Jan 28, 2015

ClassikFan said:
Having had a search on here it seems that the resistor pack problem shows as the fan only working at full speed. Mine does nothing on 1 or 2 but works on 3 & 4 so what is the likely hood that the resistor pack is the problem?

So i presume that your's is without digital aircon then if you inists on the resistor pack or you missed some of my other posts

...the resistor pack is not a tranzistor

and that full speed issue is happening in case of power tranzistor failure on AIRCON modells which dont have a resistor pack cos they have the power tranzistor instead, the NON-AIRCON (classic heater) modells dont have a tranzistor but a rezistor pack which has 3 resistors within , two of them(0.85/1.71 ohm) in serial connection involved in speed 1 and 2 and one in line(0.32 ohm) for speed 3, on speed 4 the motor gets direct earth...so if one of the first two resistors is shot there will be no speed 1 and 2 but the 3'rd inline(0.32 ohm) resistor is still good it will give the 3'rd speed and as 4'th is direct to earth the resistor pack doesnt matter, you can check the resistor pack with multimeter, unplug it and measure resistance on it's terminals, i presume that the 0.85 ohm resistance is blown, there's a missmatch between the diagram and connector view's wire colours so to make sure measure across where the black wire goes and all the other's and you'll find an open circuit if the problem is there... if you have basic knowledge about electrics you'll understand what i'm speaking about from the attachments

ClassikFan · Jan 28, 2015

Thanks sierrafery. You are a mine of information. I'd better get my multi-meter out!

Evil Elvis · Feb 2, 2015

I am having similar issues with my 1999 disco 2, i know nothing about electrics but i bought a new resisitor like the one in your thumb nail, I have the disco with aircon too, is it the right type? My friend got me the part, I have a rhd but cant seem to find the part in the car, there is however a small black box to the left of the heater matrix, I was wondering if that was what i should be looking for?

is this what i should be replacing?

Evil Elvis · Feb 2, 2015

He got me one of these:

but I cant work out where this goes?

sierrafery · Feb 2, 2015

read post #12 again

Evil Elvis · Feb 3, 2015

I have, im not a mechanic can you please spell it out to me? I have taken out the fan and it runs with 12v through it, I have taken out the little black box with the heat sink at the back of it and its very corroded, Im guessing that maybe my issue? with the fan out I can see there is not a stc3133 there

sierrafery · Feb 3, 2015

I dont know what to say more, if your's is with aircon and the problem was like described at the beginning of this thread which means it worked only on high speed you must fix the power tranzistor as it was explained clear enough...if the fault is different open a thread with yourt specific problem cos here it's futile

biggeeeee · Feb 3, 2015

Any chance you could delete your picture as its massive. I've resized it

blue beasty · Feb 4, 2015

biggeeeee said:
Any chance you could delete your picture as its massive. I've resized it

As if I haven't got enough to do

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