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Discussion Starter #1
Hello everybody :)

Yesterday my GTV decided that the aircon/heater would be on full blast forever (even when engine off and key out). The only way to switch it off is remove the fuse. I suspect that I might have got some water in the electrics somewhere causing a short. Fortunately everything else seems to work.

Anybody have any idea of how to go about fault finding this and sorting it out, or should I just take it to a garage?
 

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The fan is permanently live and is earthed by the speed controller. With the key off, the speed controller normally switches the fan off.

The speed controller is where you need to look. You'll find it in the heater unit adjacent to the fan. It'll have a thick orange and a thick black wire and thin orange, light blue and yellow wires.

Note, if is is beyond repair ( drying out? ) you cannot use a speed controller from a phase 1 ( they are totally different ). The speed controller in the phase 2 is also used in some 156s.
 

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Fan speed resistor mate, I had the EXACT problem the other month, Contact Autolusso or go on their Ebay store, I paid £19 for mine delivered, 5 minute job to install. However mine is a PH2 so it was the IC controlled version unlike the PH1 which is a resistor coil version.
 

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Discussion Starter #4
Thanks for the responses I shall have a look in daylight and see if I can see anything that looks likely. Sorry for the stupid question but I really don't know where anything is in one of these (p2 gtv) so roughly where in the engine bay is the speed controller/fan speed resistor?
 

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Behind the glove box/passenger airbag in the passenger footwell. With your head in the footwell, you'll see a circular plastic housing ( fan ) and between it and the centre of the car you'll see an oval shaped speed controller with the 5 wires described previously.

EDIT : Picture here >
http://i1134.photobucket.com/albums/m615/pkr1/Samples/2011-09-26_11-22-20_DSC_001.jpg

( There may be some variation with year, but it's basically the same ).
 

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Discussion Starter #6
Thanks again, I can see it now :)

Now, and again please excuse these questions if they are stupid but:
1) Do I need to disconnect the battery before taking this out to inspect?
2) what screwdriver bit would I use on the two screws holding it in? I only have standard torx bits.
3) It's kind of awkward to get access, so is there a way of releasing the whole unit to improve access? Or would that be more trouble than it's worth?

Thanks again for the all the help :cool:
 

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Colly, it's more simpler than you think, push the seat all the way back, lay on your back and look up with a torch, it might be bolts on yours as mine were 2x 5mm bolts (Nickel plated) the resistor pack is just at the rear of the main housing, as a temp fix, just unplug the fan which is a blue plug with 2 pink-ish wires connected, that will stop your car from having the fan on with ignition off. As for the resistor box, it's roughly 8cm width by 4cm depth, remove the 2 bolts and pull downwards, disconnect the 2 plugs and you're now able to install a new one :)
 

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Discussion Starter #10
Thanks again everybody, I've got it out (it was on 5.5mm hex bolts) and it's an IC.
I can't see anything obviously wrong with it from a visual inspection (see image). Is there a quick test I can do before ordering a new one?
 

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My guess is that it works by pulse width modulation. One day I'll hook an oscilloscope to mine to check that.

If so, the two large heatsinked devices in the centre are probably MosFET devices. The surface mount IC will control the MosFETs depending on an input signal from the climate ECU.

That's all guesswork!

Testing would probably be quite involved starting with the output signal from the climate ecu. I can't really help more on that at present.
 

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Discussion Starter #12
Success! :lol:
Bought a used unit from Autolusso for £20, fitted it today, and I now have lovely heat and A/C back.
Thanks for the help, this has saved me £££££ :)

Last question - is there any commissioning to be done? I just left it running for a few minutes with everything on, and then wen through all teh other settings making sure it picked them up. I haven't tried to reset the ecu or anything.
 
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