'89 Tempo/Topaz Fan Control Module Q

Have an A/C-equipped '89 Tempo/Topaz with an inoperative radiator fan.
I jumpered the fan to the battery, it works. I jumpered the relay on
the drivers side headlight, it clicks and my multimeter says it has
continuity when energized. I also tested the coolant temp sensor near
the thermostat and it has continuity when the engine is hot.

According to the Haynes, that leaves the cooling fan controller behind
the glove compartment. The book does not describe any testing
procedure, is this one of those replace-and-hope-that-was-it kind of
parts? The kind of auto repair that I hate?

Any advice is appreciated. Thanks!!

P.S. And why did Ford need such a complicated fan system, anyway? How
about a relay to kick in the fan when the A/C was on, the engine was
hot, or both? Seems to be a whole lot easier and cheaper to me!

> wrote in message
ups.com...
> Have an A/C-equipped '89 Tempo/Topaz with an inoperative radiator fan.
> I jumpered the fan to the battery, it works. I jumpered the relay on
> the drivers side headlight, it clicks and my multimeter says it has
> continuity when energized. I also tested the coolant temp sensor near
> the thermostat and it has continuity when the engine is hot.
>
> According to the Haynes, that leaves the cooling fan controller behind
> the glove compartment. The book does not describe any testing
> procedure, is this one of those replace-and-hope-that-was-it kind of
> parts? The kind of auto repair that I hate?
>

I can't even attempt to rationalize the Ford engineer's reasons for the fan
controller design, but I can tell you that when you find the relay and look
at the wiring harness connector you will see that it is practically melted
from the current going through the fan power supply wire. The relay may
still be good, but the terminal in the connector will most likely be burnt.
At least that has been my experience with that particular model. I would say
the design is flawed in that it doesn't hold up to the heat caused by the
cooling fan current once the fan gets a little older and starts drawing a
few more amps that it should. Proper diagnosis should include checking the
fan current draw to make sure it is not above factory specification and
perform voltage drop tests across the harness connections to make sure there
is not any resistance that could cause them to heat up and melt the
connector.

--
Kevin Mouton
Automotive Technology Instructor
"If women don't find you handsome, they should at least find you handy"
Red Green


> Any advice is appreciated. Thanks!!
>
> P.S. And why did Ford need such a complicated fan system, anyway? How
> about a relay to kick in the fan when the A/C was on, the engine was
> hot, or both? Seems to be a whole lot easier and cheaper to me!
>

> from the current going through the fan power supply wire. The relay may
> still be good, but the terminal in the connector will most likely be burnt.

Hmmm. I didn't see any burned connectors but then again, I wasn't
looking for any. I'll double check and probably hit the junkyard for
the parts, hey value priced parts for a value priced car.

Thanks Kevin for the info!

On Fri, 09 Jun 2006 20:59:19 -0700, > wrote:

> Have an A/C-equipped '89 Tempo/Topaz with an inoperative radiator fan.
> I jumpered the fan to the battery, it works. I jumpered the relay on
> the drivers side headlight, it clicks and my multimeter says it has
> continuity when energized. I also tested the coolant temp sensor near
> the thermostat and it has continuity when the engine is hot.
>
> According to the Haynes, that leaves the cooling fan controller behind
> the glove compartment. The book does not describe any testing
> procedure, is this one of those replace-and-hope-that-was-it kind of
> parts? The kind of auto repair that I hate?
>
> Any advice is appreciated. Thanks!!
>
> P.S. And why did Ford need such a complicated fan system, anyway? How
> about a relay to kick in the fan when the A/C was on, the engine was
> hot, or both? Seems to be a whole lot easier and cheaper to me!
>


The cooling fan controller on those cars was notorious for failing. There
is a good chance when you pull it you will see the plastic is melted at
the plug contacts. If everything else works and the fan still doesn't come
on you have pretty well isolated the problem to it by process of
elimination. If you can't find one that's any good it is possible to
replace it with two generic SPDT relays. In my experience they will
outperform the OEM part. Sorry but I don't remember the wiring particulars
it's been years since I've worked on one of them. It's a simple circuit
though. If you can find a schematic you should be able to figure it out.
--
Using Opera's revolutionary e-mail client: http://www.opera.com/mail/

On Sun, 11 Jun 2006 20:27:34 -0700, > wrote:

>> from the current going through the fan power supply wire. The relay may
>> still be good, but the terminal in the connector will most likely be
>> burnt.
>
> Hmmm. I didn't see any burned connectors but then again, I wasn't
> looking for any. I'll double check and probably hit the junkyard for
> the parts, hey value priced parts for a value priced car.
>
> Thanks Kevin for the info!
>

Those controllers are usually bad from the junkyard if you can find a
junkyard that hasn't crushed them all already anyway. My solution was to
duplicate it's function with two discreet SPDT relays. As memory serves it
took about 10 minutes to analyze the circuit and wire it up from scratch,
that's with a good schematic.

--
Using Opera's revolutionary e-mail client: http://www.opera.com/mail/

Thanks again guys. I finally dug into it some more and realized I
wasn't getting +12VDC to the harness where the relay plugs in. Traced
it back to a blown fusible link. The fan works now... finally!

I guess next time I'll check one more thing before throwing up my
hands.