Ford Focus (1998 - 2004) - 03 1.6 Repeated Resistor Failure

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Tue 2 Jun 2009 22:15
03 1.6 Repeated Resistor Failure - cjm1066
I originally replaced the resistor in Dec, the 3rd one has now failed. No2 was returned to Ford for assessment, no3 purchased from a difference source in case there is a faulty batch. The multi-pin plug looks to be 100%.

One suggestion is that fan motor is defective (changing its resistance) and this is causing early failure of the resistor. The car did suffer the dreaded water leak 2 years ago so the fan may have got damp ? which may have damaged it.

Any other likely reasons for the resistor to fail so quickly?

Thanks

Edited by Dynamic Dave on 02/06/2009 at 22:28

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Thu 11 Jun 2009 13:35
03 1.6 Repeated Resistor Failure - Statia
Which resistor?

Simple explaination to me is that the resistor is burning up as more current is being drawn through it than it is rated for. Some electronic circuits use resistors as a mock fuse by this mechanism but I haven't seen this design used in car electronics.

Sounds like a defective fan may be the problem. Grab one from scrappy and swap it out if I was you.
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Tue 16 Jun 2009 22:38
03 1.6 Repeated Resistor Failure - damadgeruk
My father has had similar issues on his 02 1.8TDdi, I believe the resistors are still intact though there is a thermistor/overheat cut-out in place for speeds 1-3, does your unit still work on 4? This seems to be a common problem. I have yet to be forced to swap out my fathers blower though it's the next step for me. David
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Wed 17 Jun 2009 23:13
03 1.6 Repeated Resistor Failure - Dave_TD
I don't know if Ford carried over the layout or not, but on my MkI Mondeo the pollen filter was directly above the resistor pack. When I bought the car the pollen filter had not been changed for some time and was sopping wet and full of leaves. The water had then dripped onto the resistor pack causing it to short-circuit. Changing the pollen filter and the resistor pack restored all fan speeds, however even with regular pollen filter changes it still ate resistor packs every 40,000 miles (or 5 months!). I believe the pollen filter could have been getting damp, dripping onto the resistors, and then with warmer weather drying out again. Maybe this could be the case with your Focus?

Hth,

Dave TD

Edited by Dave_TD {P} on 17/06/2009 at 23:14

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Thu 18 Jun 2009 08:30
03 1.6 Repeated Resistor Failure - AndyT
...Or the pollen filter could be blocked, causing the thermal fuse in the resistor block to overheat, due to lack of airflow.
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Thu 18 Jun 2009 20:54
03 1.6 Repeated Resistor Failure - punkhead
you are right in suspecting the heater motor is causing the problem I have changed a few of these because of the same problem all have been caused by the water leak into the motor via the pollen filter.
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