PING : Electronic experts.

What is the component arrowed called, I want to buy some to fix this if
I can.

Thanks

http://www.flickr.com/photos/spraypolish/5105918299/

 

Its a heater contorl resister of the heater in my Focus if that helps, 4
settings , so I presume that it relates to 3v 6v 9v 12v , or maybe not.



No other marking at all on the part.

 

Meant to sat the settings are the speed of the fan.

 

Probably a thermal fuse
http://www.admac.myzen.co.uk/Focus1/

 

If the blower fan only works on the fastest speed it is a thermal fuse
and it has blown. See my other post for a link/circuit/parts.

If the fan has failed completely then it is either a conventional fuse
in one of the fuse panels, either in a box under the bonnet or on the
fuse panel behind the glove compartment.

The other failure mechanism is the switch itself mechanically failing
which probably necessitates removing the radio to get at the screws that
hold the switch fascia in place. If you are going to remove that radio
make sure that you have the security code for when you re-instal it. If
you don't have the code make a note of the serial number (possibly
starting with an M) and post back.

 

Maplin now want around 80p for a fuse but if you have a store near you
may find it cheaper to pick it up.
<http://www.maplin.co.uk/Module.aspx?ModuleNo=470&OrderCode=RA15R>

Rapid want between 25p and 47p for a fuse but may be the better outlet
(incl p&p) if you go mail order
<http://www.rapidonline.com/Electronic-Components/Sensors/Thermal-Sensors
/Miniature-thermal-fuse/64690/kw/thermal+fuse>

CPC (small order charges of around a fiver) £2 for a pack of 5
<http://cpc.farnell.com/thermodisc/g4a01184c/fuse-thermal-w-e-184c/dp/FF0
1030>

RS may have a trade counter outlet near you (approx £3 for pack of 5)
<http://uk.rs-online.com/web/search/searchBrowseAction.html?method=getPro
duct&R=1769312>

Note: you may have to make up your own mind as to temperature based on
the marking on the old fuse or with research in the newsgroup archives
for similar fixes - it is a common failure mechanism.

On my Focus the conventional fuse in series with the speed control
module is rated at 7.5A so a thermal fuse as detailed above rated at 10A
will be OK.

 

Obviously I cannot see this, but there is a third thing about electrolytic
capacitors, and that is you need to get them in the right way around or they
tend not only to not like it, but depending on the use, can damage much of
the rest of the equipment if you are not careful.

No idea what the device you mention is.

Brian

 

I find it hard to believe that you can know which part of a speed control
board is the faulty one myself.
I'd suggest its more likely to be an active device. You do not mention the
symptoms either.

Brian

 

The common failure mechanism in a Ford Focus internal cabin air blower
speed control is the failure of the thermal fuse.

There are no active components in the control circuit. The control is
extremely crude, but effective. It is designed with the KISS principle
in mind. With minor variations, other car manufacturers use same design
and have the same failure of the thermal fuse.

In the fastest position the blower motor is connected across the 12V
supply, via a conventional fuse and a four position mechanical switch.

For the three lower speed setting the voltage across the motor is
dropped down via three large wire-wound resistors. A thermal fuse in
series with these resistors stops them catching fire

I agree it would help to know the exact problem as there could be other
failure mechanisms. All the others are likely to be simple mechanical
failures of a fuse, switch or motor.

If the thermal fuse has failed the question would be why?

Old age and bad luck is one reason.

Another common reasons on a Ford Focus may be a blocked cabin pollen
filter restricting air flow through the motor and the control board
which is bolted into the air flow.

If the cabin pollen filter is replaced the seal on the cover often fails
allowing water to enter the passenger foot well. This water will run
through the motor and onto the control board. On older models, and
perhaps the latest model of the car, the pollen filter cover forms part
of the windscreen seal. The plastic clips tend to break when the cover
is removed and the seal at the bottom of the windscreen is not soundly
made on re-assembly.

In my experience, a thermal fuse replacement alone fixed the problem for
further 5 to 6 years of my ownership of a car. On a friend's car the
motor shaft had become rusty and was binding a bit. This was cured by a
thermal fuse replacement and one drop of engine oil, applied with the
drip stick, to the shaft close to each of the motor bearings.

 

Would you like to reconsider that?


--
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Tyger, Tyger Burning Bright (Remove rust to reply)
116 Giulietta 3.0l Sprint 1.7 GTV TS GT 3.2 V6
Triumph Sprint ST 1050: It's blue, see.
www.cuore-sportivo.co.uk

 

Spend £14 and save yourself the hassle
http://cgi.ebay.co.uk/FORD-FOCUS-MO...arts_Vehicles_CarParts_SM&hash=item1c1363d766

 

Heh. I was thinking -57C was a bit conservative.

 

Usdual fault, as stated, filter failing and not being replaced, water
leaking into motor rusting shaft, That has been fixed.

This unit and another has fallen gradually, fist , speed 1 & 2 wouldn't
work, then speed 3 & 4 failed.

Very common fault, on the Focus and Mondao, same unit. Thermal fuse in
engine area is not blowing.

 

Ahh makes sence, no names or anything else on the 'fuse, the photo is a
stock photo the 2 I have here have no markings on the windings.

 

Yes, Local Ford want £29 +VAT, I'm getting one from the 'bay' for £6 but
I would like to 'fix' it myself, just for the pleasure of knowing.

 

Speaking as one who has spent countless hours fixing things that would have
been much easier to replace at little cost, I respect your determination.

 

Idiot.

I think it quite impressive that Brian manages to post at all,
considering he is blind.

As he physically can't see where his cursor is to avoid top posting I
think it would be a little difficult for him to do so.

 

Yebbut 216 degrees is a common value for thermal fuses e.g
http://www.lmelectricalspares.co.uk/microtemp-thermal-fuse-216-deg-1529-p.asp

 

Could be but one end seems to be pointy. It could be a diode or even a fuse.

--
Malc

Rusted and ropy.
Dog-eared old copy.
Vintage and classic,
or just plain Jurassic:
all words to describe me.