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Discussion Starter #1
I have been searching for a thread on this issue and I have tried some of the ideas but nothing has worked.

I own a 2003 Ford Focus door Wagon ZTW, which as it seems has quite a few differences in wiring as I have been searching, so here is the issue.
The passenger side fan is not turning on, driver side fan has worked fine including turning on at low and high speed. I checked the Passenger side plug for current and it showed 13.5 volts, so naturally I assumed the motor was bad.
Purchased a new Spectra Premium fan module and installed it, everything worked great, about a day went by and once again the passenger side fan is not working. So I checked the voltage again and its 13.5 volts at the plug. Could't believe it fried another motor so I started to check the wires after the plug on the fan side and was absolutely puzzled, this is where its gets really strange....with a volt meter on the plug wires from the wire harness for the passenger side fan it was reading 13.5 volts, as soon as I touch the two connectors with a test light, with the volt meter on the connectors its looses all power. So even the slightest draw from a test light causes that fan circuit to loose power. I have a question, do both fans eventually tie in together inside the fuse relay box or are they on separate circuits? Looking for where there could be a bad connection or a frayed wire not less the computer operates the fans separately of each other on this model car and then I have a whole other issue.

All relays and fuses have been replaced

Thanks for any info you guys can provide.
Matt
 

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Sounds like you have high resistance in the power wire. If you're measuring 13.5-ground with it unplugged and 0 plugged in (measured from the plug to ground) then that means the power wire has a high resistance problem.

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Plug a test light into the socket and to ground. Test voltage from the positive battery terminal to the positive side of the test light and from the negative battery terminal to the negative side of the test light. Tell me the readings and I'll see what my brain thinks.

Cal

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Discussion Starter #4
When I get home I will do that, when I was testing it I was only using the two wires from the plug to test, not grounding out to a ground on the car. I will test both ways and see if I get different readings.
 

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I own a 2003 Ford Focus door Wagon ZTW, which as it seems has quite a few differences in wiring as I have been searching
Differences as compared to what?

All 00-04 Zetec cooling fans are wired in parallel meaning they should both operate any time the cooling fans are required by the PCM. They are either both running in LOW or both running in HIGH. The PCM energizes either the LOW speed fan relay which powers both fans thru a resistor or the HIGH speed fan relay which powers both fans directly (bypassing the resistor).

Paul

 

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Discussion Starter #6
Ford mechanic said that my car had a different wiring on the fans, but I have seen the diagram you have that contradicts that. But if that is the correct diagram then I only need to chase down a wiring issue. Probably in the Fuse/relay box.
Thanks for a better exploded view of the wiring.
 

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Ford mechanic said that my car had a different wiring on the fans, but I have seen the diagram you have that contradicts that. But if that is the correct diagram then I only need to chase down a wiring issue. Probably in the Fuse/relay box.
Thanks for a better exploded view of the wiring.
I guess I should have asked: what engine does your 2003 have?

Paul
 

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Discussion Starter #9
Well I went home to test it and of course everything was working perfectly. Both fans are running. I still checked the current though, what I got was positive wire to the fans and positive lead on the battery were always the same amount. between 12.5 and 13.9 depending on the engine RPM because I was throttling to see if anything changed. They never changed. That was also grounding out to the battery or the negative lead on the harness. So as it stands at the moment it is working fine. Once the fan stops running again I will check the voltage again.
 

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Check (at operating temp, of course) what the fans do with ac off vs ac on.
That can help narrow things down a little more for ya.
Well I went home to test it and of course everything was working perfectly. Both fans are running. I still checked the current though, what I got was positive wire to the fans and positive lead on the battery were always the same amount. between 12.5 and 13.9 depending on the engine RPM because I was throttling to see if anything changed. They never changed. That was also grounding out to the battery or the negative lead on the harness. So as it stands at the moment it is working fine. Once the fan stops running again I will check the voltage again.
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Discussion Starter #11
Check (at operating temp, of course) what the fans do with ac off vs ac on.
That can help narrow things down a little more for ya.

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Passenger fan is not working again...I did more tests per your question. Cold...Fan Passenger fan will come on when the AC switch is on, only comes on with AC until up to temperature, Once up to temperature if I turn off the AC fan will still be on high until temperature comes down and then it goes into "slow" mode. If I hit the AC button spins up to "high" mode again.

So it seems to me that the the driver side fan is operating correctly. Now my question is are the fans hooked together or does the computer drive each fan independently. Going off the Diagram on this thread they should be hooked up together.

Also the passenger voltage varies from 10.5 volts low speed and 13.2 high speed just like the driver side fan until I put the test light on it then it cuts out completely.
 

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Now my question is are the fans hooked together or does the computer drive each fan independently. Going off the Diagram on this thread they should be hooked up together.
As I stated previously:

All 00-04 Zetec cooling fans are wired in parallel meaning they should both operate any time the cooling fans are required by the PCM. They are either both running in LOW or both running in HIGH. The PCM energizes either the LOW speed fan relay which powers both fans thru a resistor or the HIGH speed fan relay which powers both fans directly (bypassing the resistor).
If only one fan is running there is either a wiring issue to the 'dead' fan or the fan has failed.

Paul
 
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