Blower fan and A/C not working

2001 Focus SE. I just bought this car. The Blower fan doesn't work. I disconnected the wiring plug from the fan housing to check voltages. While disconnected, both wires indicated 12 volts... This isn't right is it? I
was expecting one hot wire and a neutral/ground wire. I also checked the voltages across the fuse in the engine compartment. With the fuse removed, same thing, 12 volts on both sides. I verified the fan itself is OK by running power to it directly.
Any Ideas? Anyone know how to properly get behind the dash to troubleshoot the switches?
Thanks!
-Dave-
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It is correct. One side of the blower is connected to 12V via a fuse (which must be okay) and the other side gets connected to ground via the switch. If you pull the plug off there is no ground connection, your measuring meter takes next to no current and so both terminals appear to be at 12V.
By any chance does the blower motor only work on the 'full' switch setting? The full setting is the switch directly putting the second terminal to ground. The other three setting go via a thermal fuse and some resistors. If the thermal fuse has blown the first 3 setting don't work but the fast one does.

Only with the wiring plug connected - not when it is apart. The ground connection is in the other half that you probably didn't check.

This suggests that you may have pulled the wrong fuse

Fan circuit for UK focus, 1.6 petrol at
< http://www.amacleod.clara.co.uk/focus/index.htm
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Alan
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<snip> By any chance does the blower motor only work on the 'full' switch

<snip>
This is the exact problem that my Mum's 1.8 Focus (UK) has...where is the thermal fuse located please? Now I know what the problem is, I can try and fix it for her!!
Thanks,
Tim
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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.
<http://groups.google.com
Type 'thermal fuse blower motor' into the search box (without the quotation marks).
The advice given for other cars is valid.
<Previous posting - cobbled together from a couple of posts>
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 capabilities. My Haynes repair manual suggest that a motor resistor is accessible by removing the blower motor but as I've no personal experience of doing this on the Focus I cannot be sure that it is the module that you may be looking for. Perhaps someone else can advise.
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.
<http://www.maplin.co.uk/
or
<http://rswww.com
I've included the references to the devices on < http://www.amacleod.clara.co.uk/focus/index.htm
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 friends car the replacement fuse is still okay after 9 months.
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 croc clip or bulldog clip as a heat-sink to the body of the fuse while soldering to reduce the heat build-up.
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.
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.
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 shaft were rusty and some lubrication (ONE DROP of engine oil from the dip-stick) was applied to the bearing area.
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Thanks for the info so far. The fan doesn't work on any speed. The A/C doesn't work either. Perhaps the two are related. Any other troubleshooting ideas?
Thanks -Dave-
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Fuse 58 (brown 7.5A) appears to be responsible for the Air Con and re-circulation control. Although there is some confusion in my Hayes manual about fuse numbering, the wiring diagrams shows this fuse relaying 12V to an electronic control module, labelled heating control, with connections to i) Re-circulation actuator and motor ii) De-icing switch iii) Air Con compressor cycling switch iv) Dual pressure switch
I note that one of the connections from the blower motor switch is an input to this heating control module so there is some interaction.
Diagram at <http://www.amacleod.clara.co.uk/focus_2/index.htm
The second fuse panel with F58 is behind the glove box in the passenger compartment on UK cars. Press the sides of the glove box to release it.
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Got it! It was the switch. When I took it apart, it was all melted inside. Must have been a fualt sometime in the cars history. Thanks for your help! Much appreciated!! -Dave-
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