Heater Fan Transistors, Which replacement....

Hi Bob, Peter.

Thanks for the info about the control wire. I'll have to re-examine how mine is behaving, as the spade connector snapped off it while I was working on the loom, and I had to crimp on a new one. I could have sworn the fan worked for a time with it disconnected, but it was so sporadic I really can't remember now!

To make a liar out of me, when leaving work tonight, the blower kicked in as soon as I started the car, but then died about 5 minutes later and has refused to run since.

Thats an interesting theory about the alternator regulator Peter. It may well be spot on, as the first time I noticed the fan was coming on after a delay, was on Monday morning when I had to stop and scrape the windscreen again, shortly after leaving home. I was standing outside scraping with the car idling for a good few minutes, with no lights or any other electrical loads on, and I heard the blower come to life. I guess that time sat ticking over was enough for the voltage to reach the 14v or so.

Tonight on the way home when it died, I had the lights, wipers, and heater rear window on, so I presume the load from these may well have dropped the battery voltage if the alternator isn't doing as it should. I'll have to measure the voltage when the car starts tomorrow, though from memory on Sunday I recall it jumping wildly up and down between 12 and 14 on a few occasions, so I think you're right.

Interestingly, this car apparently had a reconditioned alternator not long before I bought it, I wonder has it had a previous issue with this. Can regulators be replaced easily enough, or am I better just swapping the whole unit?

Thanks again for all your help.

Ciarán

This post has been edited by Ciaran on November 15, 2007 01:34 am

Hi Ciaran

It could just possibly be that the alternator belt is slipping. You should have pretty well 14v all the time the engine is running.

Peter.N.

FWIW I had 3 different recon alternators on mine (old one) in a 12 month period, first one went in dec 04, failed oct 05, replaced by indie under warranty, failed again within a few weeks, again replaced under warranty nov 05, OK since fingers crossed :-) However more stopped working than just the fans.

Evening guys.

I had a few moments spare the other night, so checked the voltage at the battery with the engine running, solid ~14v thankfully.
Interestingly, I now think its definately a wiring problem, as I've discovered anytime it stops, if I just move the wires ever so slightly, just before they enter the plug at the blower, then it kicks straight into life again. I'm guessing they're either high resistance, or loose inside the plug connectors somewhere.

Has anyone else attempted to replace the plugs. Is it even possible, i.e are new plugs obtainable? If not, I guess I could just solder individual spade connectors onto the end of the relevant wires after cutting them back slightly, but I'd rather have the proper plug if at all possible.

Aren't these winter mornings a joy!

Ciarán

Hi Ciaran

Do you have o copy of the spec for the original TI blower transistors?

John

Hi John

I am reliably informed that a suitable replacement is a MJ11015. I have used any available TO3 PNP power transistors rated at 15 amps or more sucessfully, although I am told that the originals were Darlington pairs.

Peter.

MJ11015 is also a Darlington pair, that is two transistors in series to increase power and latch at difficult loads and also two shunt resistors inside.
I'm into it this weekend!

Fair enough. I havn't personally used those but they were recommended. I used straight PNPs and they worked OK. Enjoy

Peter.

Sorry John, only just saw this, but looks like Peter has helpfully sorted you out

I was unable to find the original transistors at the time (must be about a year ago now I had this prob ), but I believe they were Motorolas, I really should have kept them for informational purposes, stupid of me really.

I went with the MJ11015s mentioned because they were the closest spec match I could get hold of, being 30a etc.

They work well save for the fact that they seem to leak a tiny bit, as in when the ignition is on, they allow the fan motor to turn very slowly even with the dash switch set to off. However other than that they work very well across all the speeds, and I haven't had a problem with them.

Ciarán

Hi All

Moved on to the next stage of this saga today. Bought a brand new fan driver module (Citroen part number 6441.78) from ebay that turned up in the post this morning. It has a couple of bright and shiny ST Micoelectronics transistors on it coded FW26025A1. I thought I had found the modern eqivalent devices so I looked it up and found that not only do ST not list them but that it was a unique device number issued solely for the manufacture of these devices to be supplied to PEUGEOT. I guess this is also why we have never tracked down the older TI device that were fitted to the original heater blowers.
Have now dug a bit deeper and got as far as the specification of the FW26025A1 as the real manufacturers in China give out spec sheets and identify the general commecial equivalent device.

Type - NPN, Case - TO3, 100volt, 20amp, 160watt, linear switching power darlington transistor.

The equivalent device is a 2N6287

If this is right then the previously identified replacement the MJ11015 is not the right choice. It is a PNP device while the spec suggests that the PEUGEOT device is a NPN device. This might well explain the reports after replacement with MJ11015's of the fan moving slowly when the controls are shut off. The effect of the difference in the devices is simply to reverse the polarity of a diode in the device. The NPN complement MJ11016 would have been a more suitable choice.

Will now set about looking for a source of supply for the 2N6287 in the UK. Mouser in the USA do them for around $3 each but they ought to be available over here as well. Will then try a pair in a spare module and see how well they work.

John

This post has been edited by xmexclusive on March 07, 2009 06:08 pm

Hi John

I'm pretty sure that the originals in my motors have been PNP, hence the difficulty in finding them. I don't think NPN's would work as they would offer a virtually short circuit. I think maybe something has been lost in translation.

I have always used straight bipolar transistors and they have always worked perfectly, without any reference I didn't know they were Darlington's.

I would suspect Ciarans problem is either due to a leaky transistor or out of range control voltage

Peter

Hi Peter

Have had another look through the sheets. Just as well I printed them out. There is an anomaly. The sheet for the Peugeot device is clearly identified as NPN but the alternative 2N6287 device is actually a complementry PNP one selected because of the ability to withstand a high peak collector current. Looks like I will have to search for independant info on the Peugeot device and also check out those on the pcb with a meter.

Searched a bit more on the internet last night. Have now found an original ST device data sheet and this also lists the Peugeot device (FW26025A1) as NPN. There are reports on the net from people who have actually tested the devices and found them to be PNP. No wonder confusion reigns. Not just a unique part number but also a unique spec for the device so there is no direct eqivalent device. At least I now have detailed specs for a number of the devices used and tried. The other plus is that the FW26025A1 is still available from stock (found at least a million) even if it is not still in production. It was not just Citroen and Peugeot that used the device in heater fans. It seems that Renault and Nissan used it as well. Will see during the week if I can corner the UK's supply of 27 devices (as of 6/3/09) that I found. The same web site found stocks available in the mid 1000's with suppliers in France, Germany, Holland and also Australia. There were also bulk supplies available from China.

John

This post has been edited by xmexclusive on March 08, 2009 11:52 am

Used to have the same problem with TVs John.

Hi All

The saga continues.

First got a bit further with the spec issue. The FW26025A1, the device actually used by Citroen/PSA on modern blower controllers is a variant of the standard 2N6287 selected from general production by testing to a slightly tighter spec than that accepted for the standard device. In the UK both Farnell and RS Components list the 2N6287 but want over £5 each and RS adds a £10 special order premium. Not good enough prices to be even worth purchasing just a few for a trial. All the FW26025A1 stockists have turned out to be wholesalers and so far none want to deal with small orders.

Just at the moment there is a UK supplier for the new control module (6441.78) offering on Ebay for £42.50 plus £3.00 p&p. Eurocare, Derby, Tele 01332 257401 & 2. They have more than 10 in stock.

John

This post has been edited by xmexclusive on March 16, 2009 09:07 pm

Hi Ciaran,

Thought I'd throw in my twopence worth.

The symptoms you describe sound to me like a dry solder joint where the spade terminals are mounted on the PCB. I think if you remove the module from the fan and look very closely (probably with a good light and a magnifying glass) whilst wiggling the spade you'll see the break in the solder joint. Just run a soldering iron over the connection on the PCB.

Hope that works. Please let us know.

Cheers

noz