Fan speed control – capacitor help

[whippet]

My fan did the common trick of stopping working except on maximum (climate control type). So I ordered up a replacement transistor per the fact sheet.

When I pulled the fan speed controller apart the existing one seemed ok but the condenser looked as if it had leaked.

I replaced the transistor anyway and gave it a try but no joy.

So I hoping it is the capacitor that’s failed, the only thing is I’m having trouble identifying what type / rating it is, can anybody help?

[francophile1947]

Fact sheet here - http://www.igmaynard.co.uk/bongo/member ... sistor.pdf

[whippet]

Thanks for that but i cant see any mention of the capacitor specs in the fact sheet.

[francophile1947]

Probably because it's nearly always the soldered connections, at the ends, that break. Also check that your heater fan is free-running, as this is the usual cause for the resistor pack failing. No idea about the capacitor

[g8dhe]

Thanks for that but i cant see any mention of the capacitor specs in the fact sheet.

There isn't a Capacitor shown on the Climate Control system, there is only a transistor for the electronic system or resistors for the Manual system, can you give a bit more explanation as to what is leaking ?

Unless your talking about on the PCB inside the actual controller maybe ?

[whippet]

The capactor is on the circuit board that sits above the transistor (there's a capacitor, resistor and diode on there).

I've not been daft have i and attacked the wrong thing? There is only the one fan speed control unit isnt there? The one that sits under the plastic cover where the heater matrix is? It looks exactly like the pics in the fact sheet so i hope it is.

[g8dhe]

Looking at the wiring diagrams;

it only shows the transistor in the module G3-04,
The picture from the Factsheet;

there does appear to be other components, the red/orange package is a capacitor, looks like a polyester type at a guess (not that clear), that is unlikely to leak as its made from solid components. Could moisture have got into the package via the pins I wonder ? In which case cleaning any muck of the board will help. I would have expected that the diode and resistor along with the capacitor are probably only there for surge / spike protection given the environment its in - but I'm making rather a lot of assumptions here - thinking about the likely circuit, only a failure of the resistor open circuit (possible) is going to cause the Fan to stop, all the other failure conditions will cause the Fan to run most likely at full speed.
Does the resistor look at all damaged I wonder, can you still read the colours off the body of the resistor ?

[whippet]

Yes that's the capacitor - the orange brown thing in the pic. I assumed it had leaked as there is a brown gunk on the terminals and some on the circuit board.

The symptoms show all the signs of the transistor going as per the fact sheet, ie the fan only working on maximum so that was the first thing i replaced, no joy though, unless i've got unlucky and bought a bad one!

I'm just scratching now for an answer now really...

[g8dhe]

That type of capacitor has its value printed on the side. The resistor value is given by the 4 (sometimes 5) coloured bands. Do you have a multi-meter at all ? In which case it might be worth checking the transistor you took out.

[whippet]

Yes i've got a multimeter but unfortunately i've thrown the old transistir now.

The capacitor is marked as IL.224 which if ive worked it out right is 0.22uf. I may be going up a blind ally with this one as ive just put some voltage through it with the ohmmeter and it seems to be building up charge, the diode seems fine and the resistor is spot on value wise. I'm just starting to wonder if the fault is elsewhere in the climate control system - possibly in the dashboard controls?

[stilldesperate]

Hi Whippet,

You seem to be convinced it's this circuit board thats causing the fan not to work, have you actually stripped the resistor pack under the bonnet to see if it has come unsoldered? Whilst you're in there, does the fan spin freely?

Apologies if you've done this, but I'm unsure how you came to the conclusion that the transistor/capacitor is at fault.

SD

[g8dhe]

SD in the Electronic version there isn't a resistor pack, its replaced by the transistor and a by-pass relay for full power.
See here ;
Manual version                                  Electronic version


If everything looks right then yes the fault could well be back into the actual control board, if you can measure the voltage on the Light Green with Black Stripe wire (LG/B) with everything working you will see a small increase in voltage as the Fan is turned up from minimum to one step less than full power. If that wire seems to be at a constant voltage greater than about 1.5 -2 volts then that would indicate that the Transistor module is faulty, if it just sits at less than 1.5 volts then that would suggest that the controller board is faulty.

[stilldesperate]

Ta Geoff

(bet you can guess which version I've got!)

SD

[g8dhe]

SD - I've had the "benefit" of having perused all the diagrams intently for the last few months
Just wish there was more info than the Wiring itself, like details of what's in each module, they only give an outline at best, and nothing other than a "block" at worst

[whippet]

Hi Geoff

Thanks for your help with this it’s much appreciated.

I’ve checked the voltage on the green/black wire and I’m getting a constant 11.5v on all speed setting except maximum. So I guess it looks like the transistor module.

Would you have any idea if the fan would run on its maximum setting when the aircon is switched on and is in auto mode as when I do this the fan doesn’t run even when I climbs to the maximum speed on the display?

Thanks

Richard