Heater fan
- Thread starter deejay38
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Right hand vertical column and the top fuse.
Chrisw8
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Just got my fan out on my Megane coz it stopped working. Just dirty contacts on fan connector. Quick clean and got heat and clear windscreen again ..... hurray
Thanks dieseldog69 but that doesn't seem to be the problem so will have to look further afield, any suggestions?
I would suggest a multimeter and wiring dia, find the connectors/components and start checking the circuit starting at 1 end and work your way along.
You say fuse is ok does that mean you have voltage there or it’s not blown?
How long has it not been working and what did it sound like last time it worked? This may give you a clue to go straight for the fan or check wiring first.
You say fuse is ok does that mean you have voltage there or it’s not blown?
How long has it not been working and what did it sound like last time it worked? This may give you a clue to go straight for the fan or check wiring first.
JUKE179r
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Check the Blower resistor pack that sits next to the blower.
I've seen those burn up from getting leaves and such stuck in the cooling fins.
I've seen those burn up from getting leaves and such stuck in the cooling fins.
Check the Blower resistor pack that sits next to the blower.
I've seen those burn up from getting leaves and such stuck in the cooling fins.
Thanks for that and will have a look.
brian47
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The power transistor on the fan control unit works like a sort of valve in this case. It has three terminals, collector, emitter and base. The collector and emitter are the terminals through which the current to the fan motor flows and the base is the controlling terminal. The emitter and base are soldered connections and the collector is through the two mounting screws.
Power transistors can go faulty in a number of ways but in this kind of circuit those faults will usually show up as either the fan motor running at full speed with no control or the motor not running at all.
They are quite easy to change, provided you're adept with a soldering iron and you're careful to retain and replace any mounting hardware such as mica insulating washers and small plastic "hole liners" and you use a small dab of heat sink compound or if you don't have any, silicone grease between the transistor and the heat sink mounting plate.
Power transistors can go faulty in a number of ways but in this kind of circuit those faults will usually show up as either the fan motor running at full speed with no control or the motor not running at all.
They are quite easy to change, provided you're adept with a soldering iron and you're careful to retain and replace any mounting hardware such as mica insulating washers and small plastic "hole liners" and you use a small dab of heat sink compound or if you don't have any, silicone grease between the transistor and the heat sink mounting plate.
Chrisw8
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Bung 12v on fan to see if it works and work backwards
sierrafery
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That's all correct but not the case here where it's about the 300 tdi's resistor pack
... the D1 doesnt have a power transistor like the D2 with aircon, the 300tdi D1s and the airconless D2s have a resistor pack p/n STC3133 .... though i can see that you answered after mr @JUKE179r confused the D2's aircon power transistor with a heater blower resistor pack 
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brian47
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@sierrafery
You're correct mate, I did respond to the previous post by writing about a power transistor.
The faults which usually occur with the resistor packs are either one of the resistors actually burning out and going open circuit or more usually one of the joints on the end of one of the resistors breaking away. That can sometimes but not always be caused by the pack overheating because the fan isn't moving enough air over the resistor pack to keep it cool.
You're correct mate, I did respond to the previous post by writing about a power transistor.
The faults which usually occur with the resistor packs are either one of the resistors actually burning out and going open circuit or more usually one of the joints on the end of one of the resistors breaking away. That can sometimes but not always be caused by the pack overheating because the fan isn't moving enough air over the resistor pack to keep it cool.
sierrafery
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Yes, even if it was some confusion at the beginning mentioning the resistor pack was a good move cos it can really be the culprit in this case... provided the fan's motor is still alive off course
brian47
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While you and I are sorting this out together, and before the thread gets forgotten, it's worth mentioning that in some cases of the D2 transistor pack, the power transistor isn't always the metal can "TO3" type, as shown in @JUKE179r's pictures, sometimes it's a square ceramic enclosure instead, but the principle remains the same.
Thanks to all who replied to my post, but the fault was somewhat obscure as all components were working as they should, except that there was no power to the relay. Got an auto electrician to come and have a look in the end but he still couldn't find the fuse, he thought it might be up behind the dash somewhere but to save time/money by-passed the original wiring with a new cable and fuse direct from ignition to relay and now all fixed! Many thanks once again to all!
