Heater Fan, Dodgy Transistors

[kiwi]

Greetings from the far side of the world!

I have just followed the excellent instructions from this site for removing and dismantling the heater fan from my 96 2.1TD. The fan would only work on max so I figured the transistors in the control module are dodgy.

The local Citroen mechanic tells me I need to buy a complete fan unit as he is unable to source replacement transistors. I can't make out any letters / numbers on the transistors - can anybody please tell me what type etc they are, and if there is a suitable (common) replacement.

Regards,
Kiiwi

[techmanagain]

Suitable fan transistors are MJ11015. It is possible to buy the small fitted printed circuit separately. no need to buy the whole fan unit. Before investing though, recheck the connections. They are known to cause the problem you have, especially as your unit is not very old.

[noz]

Hi Kiwi,

I don't know if we're talking about the same thing here but by the 'instructions' I assume you mean the 'How To' file called heater.pdf found here:

http://club-xm.com/forum/index.php?showtopic=279

If so, you can see the transistor code in Photo 11. They are Motorola TI829-1. The ones techmanagain has mentioned may be equivalent replacements, I'm not sure. I'm no electronics expert.

Whilst it has been known for the transistors to become faulty it is far more lkely that the connections have become corroded over time. The whole electronic assembly is located in the airstream before the heater matrix. Therefore they spend at least 6 months per year in cold, damp conditions and there's no environmental protection for them. In the first instance I would try cleaning up everything and checking things out with a meter. If your Digital VoltMeter (DVM) has a diode testing facility (most do) then you can easily check out the transistors before going to the bother of replacing them.

Please let us know how you get on.

Cheers

noz

ps
if you put your model and RP number in your signature it makes it easier when answering your queries if the model is known.

[Peter.N.]

The transistor numbers on the blower control module are of little relavance as they are probably obsolete by now, in fact I think that the first ones I used as replacements are obsolete now!

I have it on good authourity that as techmanagan says, the MJ11015 are the current replacements, I believe also that they are rated at 30 amps, the ones I used were only rated at 15 amps and I never had a problem again with those, so the MJs should do a belt and braces job.

Peter.N.

[kiwi]

Hi,

Thanks for the replies. The connectors seem to check out okay - they are all very clean and firm. I have yet to invest in a digital voltmeter so will have a tech type person check the module for me this week.

Interesting that I had no electrical problems (at all!) until the battery died because I was overseas last year and the car probably wasn't being used enough. Since then I've had a succession of electrical niggles, ranging from an intermittant rev counter to an errant ABS light. The latest niggle is the gear position indicator panel on the dash has stopped working. Probably time to trade in my old analogue meter for a DVM!

Are the MJ11015s brand specific or is that a generic number common to several manufacturers?

Regards
Kiwi

[techmanagain]

The reference given is is in the Motorola range of numbers which should be available worldwide. I see from some I have to hand that they are not branded as such but have a marking -which may be their trade mark - of three semiconductor arrows on the face.

[xmexclusive]

Hi All

I have had a look for fan transistor stockists. I cannot find any reference to to original TI 829-1 transistors.
The replacement MJ11015 is a PNP Power Darlington device in a TO3 casing made by ST Microelectronics. It has been around for about 20 years as it is listed in my 1988 MAPLIN catalogue but not in the current one.
It is listed in the current RS catalogue as Stock code No. 295-163 at £4.98ea plus vat. (£2.72ea for 100 plus).
I will keep looking for a cheaper source and for the spec of the original devices.

If anyone wants details of the RS branches then look on www.rs-components.com

Regards

XMexc

[xmexclusive]

Hi All

More generally on fan motors I was looking in a scrap Xantia the other day that the dash had been ripped out of. The fan motor could be seen and appeared to be identical to the XM one. Can anyone confirm this or do I have to go back and take it out to check. I also had a look in a Pug 406 diesel and was surprised to see a few very XM'ish components including Mk2 type drivers window motor, cruise switch, immobiliser keypad and engine compartment fuse box. The latter item Pug install inside a larger weather proof box so it will be worth taking one out to see if it has avoided XM corrosion problems.

Regards

XMexc

[Peter.N.]

Yes, I believe that the Xantia blower is the same.

Peter.N.

[kiwi]

Hello all,

The blower saga continues. I have finally managed to get the time to take my Fan Speed Control Module in to be checked. Turns out the transistors are shot, as is the small yellow resistor on the back side of the control module. Have ordered some transistors but the resistor doesn't have any markings on it. Does anyone know what type / value this resistor is?

Regards
Kiwi

[Peter.N.]

I have never had any trouble with a resistor, in fact I didn't know there was one! I would check it with an ohm meter just to make sure.

Peter.N.

[kiwi]

Hi,

The resistor is the yellowy / gold one in the picture in the attached file. I'm hoping someone might know what type it is.

Regards
Kiwi