The thermal fuse has blown. Unfortunately the thermal fuse is part of
the blower resistor assembly.
<From previously posted articles to this group>
I've fixed the same fault on other cars but I haven't done this myself
on a Focus. The resistor and fuse assembly is usually mounted in the
blower motor air stream and I believe that you can get to the resistor
assembly by removing the blower motor in the Focus. Release the glove
box by flexing the back plastic sides (a _tiny_ bit of force may be
required). The glove box then hangs out of the way and you can see the
blower motor and fixings.
Below is what I have advised before but it is worth getting a second or
third opinion from the news archives at Google groups.
Type 'thermal fuse blower motor' into the search box (without the
The advice given for other cars is valid.
The fuse is a two legged device which when it reaches a preset
temperature blows permanently open circuit.
I would assume that the way the module is constructed that the fuse
alone isn't a replaceable part and that a dealer would charge for the
whole module. However it is a do-it-yourself fix if you can find the
motor 'resistor module' and have some basic electrical soldering
In the UK the a replacement thermal fuse (for the do-it-yourself repair)
can be obtained quite cheaply (0.5 GPB or less than $1 US) from
electronic component stores.
I've included the references to the devices on
When buying the replacement fuses I've guessed that the one I needed was
towards the higher end of the temperature range (150+ degrees C).
On one car I owned the replacement fuse didn't blow again in 6 years
(the car was scrapped after that). On a friend's car the replacement
fuse is still okay after 9 months.
Before replacing the thermal fuse check it with a meter to see if it
open circuit or temporality short across it to see if the motor works on
the lower settings.
Despite the warnings about not to solder I've used a high wattage
soldering gun and _quickly_ soldered at the ends of the leads.
Obviously as it is a one time thermal fuse leaving the soldering iron in
contact too long will heat up the whole device to a temperature where
the fuse blows. As they are cheap it may be worth ordering a couple -
just in case :) You could attach a crocodile clip or bulldog clip as a
heat-sink to the body of the fuse while soldering to reduce the heat
Cut the old thermal fuse out but leave about quarter of an inch of the
lead on each side that is crimped to the terminals on the assembly.
Leaving a bit of the old lead in place will make soldering the new
component in easier. Soldering to the terminal post is difficult unless
you can clean it up with a small file.
The problem may have been caused as a result of water getting into the
system and the blower motor not running as smoothly as it should. On
previous repairs the motor shafts were rusty and some lubrication (ONE
DROP of engine oil from the dip-stick) was applied to the motor shaft
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