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Discussion Starter #1
Car has 78,000 miles. At 18,000 computer failed and I had to use relay and an ignition signal for manual "key on" operation. BTW the system has been troubleshot every last connector and multiple component substititions*. The fan stops when the engine reaches normal temps. I believe it may be the fan motor brushes.

Standard Caveat: 1,400 mile trip to the US border. Two hundred sixteen dollar FedEx charge plus Mexico import tax.

Are the brushes changeable? Anyone done this or is the sucker spot welded together? The bearings are great.

*all the way to the CPU input pin
 

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Virginia Gentleman
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The fan stops when the engine reaches normal temps.
That's completely normal. Once the coolant reaches operating temperature as sensed by the CTS, than fan will cycle on/off as necessary. If you have the AC or defroster on the fan will cycle on/off to help with keeping the freon at the proper temp. Generally speaking the fan will cycle on when the engine temp reaches ~ 220 F (about 1/2 on the gauge) and remain on until the temp drops to about 190 F (about 1/3 on the gauge).

The only time the fan should not cycle on is at hwy speeds over 35 mph. At that speed there is enough air flow that the fan is not necessary.

I assume you are referring to the radiator fan.
 

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Discussion Starter #3
The control was bypassed many years ago, totally, ignition operated. When the key is switched on, the fan comes on, when the ignition key is shut off the fan goes off. 100% duty. But the fan STOPS now when the engine gets warm and I imagine it would stay stopped even when the engine heated up to become a puddle of molten aluminum slag. Re-read my priginal post. K-cars are VERY rare down here. Most have run away to China.
 

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Most of these fans are good for many years. My 91 Spirit has over 300,000 miles and I have only changed the relay 1 time; never the fan. I'm in FL so the fan runs a lot (anytime the AC is on).
I'm sure hooking the fan up to run, anytime the ignition is on, shortened its life, assuming that is the problem.
 

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KOG
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And it could be the ignition switch as it's not intended to take that much load. If you're using the switch just to turn on the fan relay then the swich may be alright and you want to look at the relay first. The fan motors are not repairable in any way.
 

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Virginia Gentleman
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Either way, the fan and related circuity was never designed to run "all the time". Back when I had my Acclaims, yes, the fan ran a lot with the AC on (I'm in VA and it gets hot like FL as well), but even then it cycled on and off. Never had to replace the fan on either Acclaim and they had 540K between the two of them.
 

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KOG said:
And it could be the ignition switch as it's not intended to take that much load. If you're using the switch just to turn on the fan relay then the swich may be alright and you want to look at the relay first. The fan motors are not repairable in any way.
He said he's still using a relay. The relay is rated for 30 amps. A good fan motor typically spikes 13A at turn-on and stead-state it's about 4.5A. That's measured with a clamp-on ammeter. A good motor will have a winding resistance of about 2.4 ohms or so. I had one that had broken down to about 0.6 ohms and still started, but pulled nearly triple the normal current.
 

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Discussion Starter #8
It rotates freely by hand but with the key on it is very feeble, sometimes needs a finger to get it started and then it rotates at around 60 RPM. K cars are really rare down here and used parts non existent. Five hundred some odd miles to the nearest FedEx or UPS office and then the same to return.

I wonder if it's a pure waste of time contemplating whether or not this fan motor has worn out brushes, and if they can be replaced. The sealed housing looks daunting. Crimped and spot welded.
 

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If you have access to a multimeter, unplug the fan and take a resistance reading across the fan contacts. Let us know what you get.
 

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David Eidell said:
It rotates freely by hand but with the key on it is very feeble, sometimes needs a finger to get it started and then it rotates at around 60 RPM. K cars are really rare down here and used parts non existent. Five hundred some odd miles to the nearest FedEx or UPS office and then the same to return.

I wonder if it's a pure waste of time contemplating whether or not this fan motor has worn out brushes, and if they can be replaced. The sealed housing looks daunting. Crimped and spot welded.
Since you have to be innovative.. to the point of considering opening up a sealed motor assembly, perhaps you could explore using a fan and/or motor off a non Chrysler EEK car. Maybe a Chevy, Ford, or whatever is in the area might be close enough to fit with some minor modifications. Maybe you'll even find an old Caravan or Voyager with a similar setup. They are all 12 volt fan motors.
 
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