Why won't my cooling fan come on??
- Thread starter Rockabetty78
- Start date
Captandave
New member
Any advice on best way to hard wire the fan. I have tried most of the fixes which were mentioned here but my fan still will not turn on without directly connecting power. I replaced the fuse box twice one used and current one is new. New fan, new thermostat, new radiator from when it overheated on the interstate which lead to putting in new head gasket. Now I just want to hard wire the fan to a switch so I can manually turn it on. I will use low speed fan so the A/c will turn on. Any advice on best way to hard wire the fan so I can sell this vehicle.
I think maybe it is bad ecu and i don't want to deal with it. I've been paying for insurance and registration for a car sitting in my carport for 2 years. Thanks for any advice.
I think maybe it is bad ecu and i don't want to deal with it. I've been paying for insurance and registration for a car sitting in my carport for 2 years. Thanks for any advice.
ozonetrooper
Member
run the ground wire of the fan to a bolt on a metal body/frame/structure .
run a wire from the positive battery terminal to a on/off toggle switch.
run a wire from the other side of the toggle switch to the fan motor.
Captandave
New member
Looking for something more specific to the sonic 1.8l car. I have done this on a dodge journey but it was a while ago. I need to know the specific wire to connect to. Prefer someone who has actually done this this to this car. Not just generic copy and past. Thanks
ozonetrooper
Member
Not sure of your capabilities, but using an OHM/Continuity meter you can determine which wire is +12/-12, and wire accordingly.
The engine size has no bearing on wiring the fan, the fan is a 12 volt appliance no matter what the car/motor is.
The resistor regulates the rpm of the fan, bypassing it will only allow for full rpm, of the fan operation.
Of course one can always refer to the wiring schematic for that model vehicle, provided one has the ability to read one, and understand what it says.
Your welcome.
The engine size has no bearing on wiring the fan, the fan is a 12 volt appliance no matter what the car/motor is.
The resistor regulates the rpm of the fan, bypassing it will only allow for full rpm, of the fan operation.
Of course one can always refer to the wiring schematic for that model vehicle, provided one has the ability to read one, and understand what it says.
Your welcome.
Captandave
New member
My capabilities are as good as my instructions. I know the a/c only operates when the lower speed fan so this is why i intend to wire it accordingly. I'll figure it out but I was hoping to hear from someone who has done this. thanks
ozonetrooper
Member
Are you talking about the blower motor for the a/c heating system ?
This is an entirely different issue, if your blower motor only operates on low setting then you may have an issue with the blower motor resistor.
The resistor is a low cost item, try replacing it.
Captandave
New member
My radiator and fan are new So I'm not replacing my resistor since it is new as well. Not talking about the blower.
ozonetrooper
Member
The blower motor is the only one you have the ability to adjust the speed (RPM) on.
The radiator fan RPM is regulated by the resistor, which derives input from the sensors to determine what RPM to operate at, it is not user configurable.
If the fan motor is a variable speed motor that uses different voltages to operate, it may by possible to wire a resistor inline with the +12 wire to reduce the voltage thus obtaining a different RPM. Not sure how one would determine the, resistance = voltage output, though.
Captandave
New member
Thanks for the great info. What I currently am doing is from a Youtube post. I took the cover off the low speed fan relay and rigged it to send power to the fan. This works well but I have to remove the negative battery cable when not using it or it will run all the time and kill my battery. I might just install an on/off switch to my battery like most boats have.
ozonetrooper
Member
The coil side of the fan relay is also a +12/-12 device. It is possible to hot wire the trigger to a switch to obtain the same results as you now have but not have the inconvenience of having to remove the battery wire to kill the trigger.
I found this in my ways and travels, it is for my year auto but you can change the year, may help you out:
https://www.startmycar.com/us/chevrolet/sonic/info/fusebox/2016
I found this in my ways and travels, it is for my year auto but you can change the year, may help you out:
https://www.startmycar.com/us/chevrolet/sonic/info/fusebox/2016
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