2004 Radiator Cooling fan always on

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notquiteflotsam

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2004
I've searched most of the similar threads and can't seem to locate the issue. My '04 recently had some work done with a thermostat housing replacement and a few other items related to cooling system. No more leaks, but I've notice the cooling fan runs most of the time. Again, I didn't notice it before, but maybe its always run like that. it just sounds like a blower more than a fan. My temp gauge remains pegged just shy of midway between cold and hot. The 60A fuse seems to be in ok shape, as does the rest of the wiring. But I'm running out of options as to what could be the cause. Anyone diagnose a root cause on this before or seen it? Thanks
 

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notquiteflotsam said:
I've searched most of the similar threads and can't seem to locate the issue. My '04 recently had some work done with a thermostat housing replacement and a few other items related to cooling system. No more leaks, but I've notice the cooling fan runs most of the time. Again, I didn't notice it before, but maybe its always run like that. it just sounds like a blower more than a fan. My temp gauge remains pegged just shy of midway between cold and hot. The 60A fuse seems to be in ok shape, as does the rest of the wiring. But I'm running out of options as to what could be the cause. Anyone diagnose a root cause on this before or seen it? Thanks
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The cooling fan has its own little micro-processor located on the driver's side upper corner of the fan engine side. The wiring for the fan plugs into it. This little piece controls the power to the fan motor BUT it gets its "on" signal from the PowerTrain Control module. The PCM tells the fan to come on when the PCM receives temperature signals from all the temperature sensors involved in controlling engine cooling. If you have a meter disconnect the fan plug & see if you have voltage all the time, if you do changes are some sensor is telling the PCM that the engine needs to be cooled down.
 
notquiteflotsam said:
I've searched most of the similar threads and can't seem to locate the issue. My '04 recently had some work done with a thermostat housing replacement and a few other items related to cooling system. No more leaks, but I've notice the cooling fan runs most of the time. Again, I didn't notice it before, but maybe its always run like that. it just sounds like a blower more than a fan. My temp gauge remains pegged just shy of midway between cold and hot. The 60A fuse seems to be in ok shape, as does the rest of the wiring. But I'm running out of options as to what could be the cause. Anyone diagnose a root cause on this before or seen it? Thanks
Click to expand...
I replaced my fan and the sensor and was still having some issues so I change the thermostat and now it runs cool
 
RDH said:
I replaced my fan and the sensor and was still having some issues so I change the thermostat and now it runs cool
Click to expand...
I don't have any issues with running hot. temp seems fine. i think this is electrical gremlins somewhere.
 
notquiteflotsam said:
I don't have any issues with running hot. temp seems fine. i think this is electrical gremlins somewhere.
Click to expand...
It could be the fan sensor I had mine change when I had new fans were put in, Remember that these cars are old and mice can get into the engine compartment when you store it, I have had that happen but luck no wires chewed
 
BluByeU said:
The cooling fan has its own little micro-processor located on the driver's side upper corner of the fan engine side. The wiring for the fan plugs into it. This little piece controls the power to the fan motor BUT it gets its "on" signal from the PowerTrain Control module. The PCM tells the fan to come on when the PCM receives temperature signals from all the temperature sensors involved in controlling engine cooling. If you have a meter disconnect the fan plug & see if you have voltage all the time, if you do changes are some sensor is telling the PCM that the engine needs to be cooled down.
Click to expand...
Thanks. I'll look into this. if it is the PCM, is there a PCM 'reboot' or do I need to replace the whole thing?
 
Before you get to far down the rabbit hole, use a scan tool to see if there are any faults that might tell you why the PCM is commanding the cooling fans to come on. Don't forget that air conditioner pressure switch will also command the cooling fans to come on via the PCM.

doug7740
1955 Thunderbird Blue

cooling-fans.jpg
 
Last edited by a moderator:
I have a question about the radiator fan operation. Isn't this a multispeed fan and if so how many speeds does it have? Lately mine seems to be running at an high speed all the time regardless of the motor temperature. When I start the car after siting over night the fan is blasting away. Is there a control module that controls when and how fast the fan should be running?
 
Boardwlkr said:
I have a question about the radiator fan operation. Isn't this a multispeed fan and if so how many speeds does it have? Lately mine seems to be running at an high speed all the time regardless of the motor temperature. When I start the car after siting over night the fan is blasting away. Is there a control module that controls when and how fast the fan should be running?
Click to expand...
I merged your post with an existing topic. As you can see, this topic has already been discussed. Use the search page or look at related posts that appear as you are typing your subject.
 
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