Troubleshooting 4Runner blower/fan problem

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Alex - 18 Dec 2006 01:32 GMT

Hi guys,

Am trying to troubleshoot a non-working fan on a '91 4-Runner and was
wondering if someone can offer some tips. (The fan in question is the
inside blower fan/AC.) It no longer comes on. This happens at ALL
speeds, includiing the highest. I've checked whatever fuses I could
think of and even have given the 'CDS FAN' relays a few wacks with a
screwdriver, just in case they got stuck... No luck.

I've taken off the glove compartment and gotten to the motor, but am
not really sure what to look for there. I've disconnected what appears
to be the power supply wire to the motor and, with the fan switch
turned all the way up, hooked up a voltmeter to all the terminals,
every which way I could think of. I can't seem to register a voltage
there. (BTW, should I still expect to read somewhere around 12V DC
there, just like I do at the battery?) This seems to imply that
there's no power to the motor, which would then rule out the motor
itself. However, I'm:

1. Not 100% convinced that I'm measuring voltage in the right place and
in the right manner
2. Even if I am, am not sure where to go look for the problem at this
point.

I've also done my best at trying to measure voltage across the relay
terminals (again, CDS FAN #1 & 2, with the engine running and fan
switch all the way to ON). And again, I've been unable to register any
kind of voltage, but am not sure that I'm doing it correctly.
(Measuring across the 'already ON' terminals, not the switched ones.)

Can someone offer some ideas to try next? Could it be the switch
itself? Is there an easy way to test that theory? Should I just get
the right relays and try those? (Are the CDS FAN the right relays?
Where can I get them?) I've also read some references in this group to
a blower resistor pack on the motor, but it sounds like since the motor
won't come on even at highest speed, when the current should flow
directly to it, this may not be the culprit.

Please help before I do any more damage. I know just enough to cause a
blackout in the neighborhood. :-)

Thanks in advance,

Alex

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Alex - 19 Dec 2006 16:00 GMT

Anyone have any ideas? Please? :-)

Thanks!

Alex

> Hi guys,
>
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>
> Alex

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Scotty - 19 Dec 2006 23:36 GMT

There should be a small resistor block located at the bottom of the heater
unit around toe level for the passenger. (Well its there in Southern
Hemisphere so Id imagine that its there in the US) I had only one speed left
on mine and the resistor wires had burnt out and for $30 I got a new one.
Alls well now and I get all speeds fine.
Try that first as you may find that low speeds havnt worked at all for a
little while and your banging around has cause the rest to go, or a terminal
wires been knocked off maybe.

> Anyone have any ideas? Please? :-)
>
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>>
>> Alex

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Alex - 20 Dec 2006 04:43 GMT

Hi,

Thanks for the advice. Think I found it, but boy is that little sucker
hard to get to and to take out. Still working on it. What am I
looking for to tell if it's busted? Would the coils be burnt out?
What about the fact that the motor doesn't come on even at top
speed--supposedly when the current is bypassing the resistors?

Thanks!

Alex

> There should be a small resistor block located at the bottom of the heater
> unit around toe level for the passenger. (Well its there in Southern
[quoted text clipped - 55 lines]
> >>
> >> Alex

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Scotty - 20 Dec 2006 06:43 GMT

> Hi,
>
[quoted text clipped - 5 lines]
>
> Thanks!

Just short out the incomming wires and you should get full speed out of the
fan, if you dont theres more to the issue.

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