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350matt, Mechanical Engineer
Category: Peugeot
Satisfied Customers: 22934
Experience:  BEng Hons, worked in the car industry for last 22 years
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I have a Peugeot 205 Diesel hatchback with a non-functioning

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I have a Peugeot 205 Diesel hatchback with a non-functioning heater blower. Motor works fine, as do all the dash controls except the blower speed knob. I think I've traced the problem to the heater control resistor (the fan speed is infinitely variable). This fits up in the passenger footwell (car is right-hand drive) between the blower fan motor and the control panel. It consists a plug-in unit with a small printed circuit, a large diode, some points and a heat sink. I can supply a photo of the unit I took out. I cleaned it all up and tried it but it doesn't work and just gets hot (very!). So I'm looking for a replacement before the onset of winter. Can you help or advise?


that sounds like the fan control unit / blower resistor to me

it controls all the fan speeds, not just the intermediate ones

I'd replace teh whole unit with a new part whihc are available from GSF

its held in place with some sealent, so its the case of running a scalpel along the glue line and pulling hard to remove it

Customer: replied 1 year ago.
Thanks for your response but this is not the type of resistor which has 3 or 4 different rated coils (I believe this is a type fitted to later models - I actually bought one of these but it is quite different). This one is held in place by two screws and connected via a multi-pin socket. I can send you pictures, if it would help. I must admit I haven't yet tried GSF but wouldn't hold out much hope.
Customer: replied 1 year ago.
I'll try to send a couple of pictures.

OK thats the earlier unit and much harder to find

might have to go the 2nd hand route

try these 205 specialists



Customer: replied 1 year ago.
Yeah, I tried 205nuts, because I have dealt with them in the past but no joy. This is apparently a common problem. I tried a scrap yard in France but couldn't locate the thing on a left-hand drive car. I can't see that anything would go wrong with the printed circuit or the points (cleaned up) so I figure it must be the diode. Do you think it's possible to replace these? Failing that, can you think of some other way around the problem? I might try to fit the later type (4-speed) control unit - but the pin pattern is quite different.

I'd agree that a failed diode is quite likely as there's not much else to go wrong other than cleaning up the corrosion with some fine emery cloth or scotchbrite

if you can tell me what part numbers are on the back of the diode unit I'll try to source a replacement part

Customer: replied 1 year ago.
It is in the car. I'll check it and get back to you in the morning, if that's OK. Thanks for your help.

no problem

Customer: replied 1 year ago.
Hi Matt - I checked the unit this morning and there are no visible numbers on the diode, even after further careful cleaning and examination under magnification (at one stage, I thought I saw a figure 9 on the side but can't be sure). I can't remove the diode to look at the back, because it's riveted on and I'm sure drilling it off would render the unit permanently unserviceable. I removed the disc which sits between the spring arm and the back of the diode and cleaned everything up - even more than I had before. Strangely, the disc doesn't seem to be ferrous.
Having done as much cleaning up as I could, I tried the unit back in the car and found that the fan would work but only slowly. The speed increased when I put pressure - manually - on the spring arm connecting the disc (and thus, the diode) to the printed circuit.
So, now I've re-tensioned the arm and further worked on the contacts of the multi-pin connector. the unit does however, quickly get very hot. Maybe this is normal and the reason it is fitted with quite a large heat-sink but I suspect that something is causing the internal resistance of the unit to be abnormally high. The max output of the fan is still considerably down on what I remember when it was working normally.


if the connection between the spring arm and the contact is poor then its will run hot as the resistance is high

and this will also cause the fan to run slowly

what might be worth considering is taking a more modern fan resistor unit such as the later type we discussed earlier and modfiying its connection to suit the earlier wiring loom

Customer: replied 1 year ago.
Yeah. Thanks Matt - that's a possibility. What you say, more or less confirms what I thought - so thanks for that. I have done about as much as I can to clean it up and I have re-fitted it now, as it seems to be working satisfactorily. I'll just have to watch it and make sure it doen't get too hot - not run it longer than necessary.


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