Honda Car Forum

The cooling fan fuse keeps blowing. I have replaced the fan reply switch
last year when one of the fans kept running even after the engine was
turns off. I have had the timing belt & a new water pump installed last
week but the car still will suddenly over heat. The cooling fan fuse is
always blown when this happens but after replacing it the car runs fine
for a few weeks. Could this be a thermostst or the thermo heat swith, how
can I tell which to replace.

willy2005 wrote:
> The cooling fan fuse keeps blowing. I have replaced the fan reply switch
> last year when one of the fans kept running even after the engine was
> turns off. I have had the timing belt & a new water pump installed last
> week but the car still will suddenly over heat. The cooling fan fuse is
> always blown when this happens but after replacing it the car runs fine
> for a few weeks. Could this be a thermostst or the thermo heat swith, how
> can I tell which to replace.

The thermostat is a mechanical device -- it just makes sure that your
engine is kept at optimum temperature. An open thermostat would make
the car run badly in winter. A closed thermostat would make it overheat
all the time. It would not cause fuses to blow, so that's probably not
it.

I also don't think it is your thermoswitch, because I believe that the
thermoswitch switches the cooling fan relay on an accord. The
thermoswitch normally switches a wire to ground -- basically shorting
one leg of the relay to ground when it detects that the heat is too
high.
If it or any wire to it were shorted, the fan would just be on all the
time but the fuse would not blow.

Intermittent problems like that are usually harder to find.

I'd carefully inspect the wires going from the relay to the fan or
possibly from your relay to the fuse (that one is less likely to be a
problem, but you never know).
It could be that one lead has been rubbing against a sharp piece of
metal and it shorts once in a great while.
It could also be that your fan has a problem. Maybe it has a bad
bearing and binds from time to time, drawing more current and blowing
your fuse. Make sure it freely spins.
If you have a current meter, put it in series with the fan to see what
its actual current draw is. It should not be anywhere near the rating
of the fuse.

There are two fans on your accord -- one for regular cooling and one
for AC operation - both driven by separate relays, from what I
remember. You could see if swapping the relays helps you (providing
they are both the same type of relay so do check if that is true).
I am not absolutely sure on this one, but you may be able to swap the
fans and see if the problem travels.
Of course, you'd have to make sure to not operate your AC under both of
the last suggestions. If the problem travels, it could be that your
fuse will blow when you run your AC.

Do not be tempted to replace your fuse with a larger one as this can
cause serious issues. Under worst circumstances, parts of your car
could catch fire.

Hope you find it.
Remco