Fan control will not work. Knob turns but fan wont come on.
 

Does anyone know what the problem/solution could be?
I have a ’97 civic sedan. When I turn the fan knob on nothing
happens. The fan isnt coming on, no heat or AC will come out.
I checked the fuses and none are blown. I pulled the knob off and the
actual metal piece turns fine...
this just happend the other day for no apparent reason.
any ideas??

thanks

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Re: Fan control will not work. Knob turns but fan wont come on.
 

"bwc" <none@000.com> wrote in message
news:1215173_e0b3a56cbc2e2899e39a1259750b79f6@auto boardz.com...
> Does anyone know what the problem/solution could be?
> I have a '97 civic sedan. When I turn the fan knob on nothing
> happens. The fan isnt coming on, no heat or AC will come out.
> I checked the fuses and none are blown. I pulled the knob off and the
> actual metal piece turns fine...
> this just happend the other day for no apparent reason.
> any ideas??
>
> thanks
>
> --
> Posted at author's request, using moderated http://www.AutoBoardz.com
> interface
> Thread archive:
> http://www.AutoBoardz.com/Fan-contro...ict250223.html

On my honda it was the motor itself. Interesting to fix but not hard per
se. 88 honda accord lxi.

Re: Fan control will not work. Knob turns but fan wont come on.
 

bwc wrote:
> Does anyone know what the problem/solution could be?
> I have a ’97 civic sedan. When I turn the fan knob on nothing
> happens. The fan isnt coming on, no heat or AC will come out.
> I checked the fuses and none are blown. I pulled the knob off and the
> actual metal piece turns fine...
> this just happend the other day for no apparent reason.
> any ideas??
>
> thanks
>


I assume this applies to all speeds? Many cars use a resistor to drop
the motor voltage for the lower speed settings, then bypass it for the
high speed. If the resistor burns out you get high speed or nothing. If
that doesn't work either, the next step is to check for voltage at the
power terminal on the motor, some cars this is easy, others it's as if
they put the blower motor on a pedestal and built the car around it.
Also you mention you checked the fuses, but you may want to try
replacing the blower fuse anyway, or at least make sure that other
accessories, if any, on the same circuit work. It's rare, but I've seen
mechanical failures in fuses where the element cracked off at one end,
still appearing intact but not completing the circuit.

Re: Fan control will not work. Knob turns but fan wont come on.
 

Thanks for the help guys!

Well mechanic says its the Heater Blower Control Motor, and its close
to 400 for the unit (or whatever it is).

Anyone know anything about that, and if I could easily do it myself or
if I could find it cheaper? Why would it just die for no apparent
reason??

Thanks again

"bwc" wrote:
> Does anyone know what the problem/solution could be?
> I have a '97 civic sedan. When I turn the fan knob on nothing
> happens. The fan isnt coming on, no heat or AC will come out.
> I checked the fuses and none are blown. I pulled the knob off
> and the actual metal piece turns fine...
> this just happend the other day for no apparent reason.
> any ideas??
>
> thanks

Re: Fan control will not work. Knob turns but fan wont come on.
 

oops the car is a 2003 not 97 (if it matters)
and the part as per mechanic is called "heater control head
assembly"

"bwc" wrote:
> Does anyone know what the problem/solution could be?
> I have a '97 civic sedan. When I turn the fan knob on nothing
> happens. The fan isnt coming on, no heat or AC will come out.
> I checked the fuses and none are blown. I pulled the knob off
> and the actual metal piece turns fine...
> this just happend the other day for no apparent reason.
> any ideas??
>
> thanks

Re: Fan control will not work. Knob turns but fan wont come on.
 

bwc wrote:
> Thanks for the help guys!
>
> Well mechanic says its the Heater Blower Control Motor, and its close
> to 400 for the unit (or whatever it is).
>
> Anyone know anything about that, and if I could easily do it myself or
> if I could find it cheaper? Why would it just die for no apparent
> reason??
>
> Thanks again
>

Sounds like it uses an electronic controller for the fan motor instead
of a simple resistor and switch. If you can open it up, there's probably
a power FET driving the motor, these tend to fail shorted though so I
would first look for hairline cracks in the solder joints under the
circuit board around this and the pins on the connector where the wiring
harness plugs in. Assuming you lack the skills to diagnose and repair
this, you could try and find someone who does, or keep an eye on ebay or
call some salvage yards. Could look online for parts suppliers but this
sort of thing is often a dealer-only part.

As for why it would die, this sort of thing happens all the time. One
major challenge in mass producing printed circuit boards is soldering
when you have a mixture of components with large heavy leads and small
light stuff. It's tricky to wave solder it such that you get sufficient
solder on the heavy stuff without burning up the small parts. On top of
this you have vibration and mechanical shock which can lead to
fractures, and temperature swings causing fatigue from expansion and
contraction, a car being a particularly harsh environment in both
respects. Components can fail as well, but I have seen surprisingly
little of this in automotive electronics. Shorted capacitor in the ECU
was the fault preventing a friend's VW Scirocco from starting, seen a
few bad ones that would cause dashboard clocks and speedometers to
function erratically or not at all in cold weather, but overall not very
many. Sometimes the design and construction are quite adequate and
things just fail, luck of the draw, it happens.

If the thing is already dead, there's no harm in popping it open to have
a look, so long as you know you're popping open the correct part.

Re: Fan control will not work. Knob turns but fan wont come on.
 

Car-part.com lists a bunch in my state, including a couple at my local
wrecking yard, ranging from $50 to $110. Give it a try!

Mike

"bwc" <none@000.com> wrote in message
news:1215283_4a01ad0eb400732a17ce372fef6980cd@0000 .com...
> oops the car is a 2003 not 97 (if it matters)
> and the part as per mechanic is called "heater control head
> assembly"
>
> "bwc" wrote:
> > Does anyone know what the problem/solution could be?
> > I have a '97 civic sedan. When I turn the fan knob on nothing
> > happens. The fan isnt coming on, no heat or AC will come out.
> > I checked the fuses and none are blown. I pulled the knob off
> > and the actual metal piece turns fine...
> > this just happend the other day for no apparent reason.
> > any ideas??
> >
> > thanks
>