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I have a real crazy question so pardon my ignorance. I had a C5 and if I was in slow traffic and it started to get a little bit warmer than what I wanted to I could turn on the air conditioner, and it would kick the fans both fans on high and it would bring my water temperature down. I just bought a 2014 C7 and I’m curious as to a manual way that I could do this or do I have to worry about it? I know the CI was a bottom breather and it sucked hot air from everywhere, not sure about the C7. Is there a way to manually activate the fans on a C7? Thanks for any input.
Calling for A/C should still turn the fan on. Note - the analog temp gauge is not accurate on the 2014s. Look at the digital display Tour mode / Performance for a good indication. On this display Engine = Coolant.
You can't just switch the fans on and off with a switch. C7 fans are variable speed. The fan controller is part of the fan assembly. The engine control module sends a pwm signal to the controller to vary the speed. Some 2014s have an issue where the fans fail to turn on and the car overheats. Stopping / starting the engine often resets the fan. The ultimate solution is a new fan / controller assembly - lots of threads on this.
Didn't really have any hi temp issues when I had a 2014, nor on 2019. Temp can go up near 220 F in hot weather / traffic. Not a problem.
You can't just switch the fans on and off with a switch. C7 fans are variable speed. The fan controller is part of the fan assembly. The engine control module sends a pwm signal to the controller to vary the speed.
So you don't think you can run power directly to the fan motors?
No, that is not how fan operation is described. The description indicates that the controller varies voltage across the fan motor to vary fan speed. There is a chart somewhere that shows coolant temp vs fan speed as well as what other conditions make the fan run.
You can try an on / off switch on YOUR car if you want...
From service manual:
Circuit/System Description
The engine cooling fan system is composed of one electric cooling fan and a cooling fan control
module. The engine control module (ECM) controls the fan speed by sending a pulse width
modulated (PWM) signal to the cooling fan control module. The cooling fan control module varies the
voltage drop across the cooling fan motor in relation to the pulse width modulated signal, which
enables cooling fan operation at variable speeds. The ECM will only operate the cooling fan at certain
percentages to prevent undesirable noise and vibration. The cooling fan control module is thermally
protected to prevent module damage in the case of a short circuit condition in the cooling fan motor
No, that is not how fan operation is described. The description indicates that the controller varies voltage across the fan motor to vary fan speed. There is a chart somewhere that shows coolant temp vs fan speed as well as what other conditions make the fan run.
You can try an on / off switch on YOUR car if you want...
From service manual:
Circuit/System Description
The engine cooling fan system is composed of one electric cooling fan and a cooling fan control
module. The engine control module (ECM) controls the fan speed by sending a pulse width
modulated (PWM) signal to the cooling fan control module. The cooling fan control module varies the
voltage drop across the cooling fan motor in relation to the pulse width modulated signal, which
enables cooling fan operation at variable speeds. The ECM will only operate the cooling fan at certain
percentages to prevent undesirable noise and vibration. The cooling fan control module is thermally
protected to prevent module damage in the case of a short circuit condition in the cooling fan motor
Ron
That is what I was thinking. Kinda like the HVAC fan motor speed is controlled by the module. So you think if you applied a 12V source to the motor itself, not the module, the motor, you can't activate it? Again, don't know. Just curious.
Yeah, not worth disconnecting the fan speed controller to jump 12 v to the fan motor. Don't know if the fan leads are accessible. The bottom line is that 2014 does not have a cooling problem unless the fan & controller assembly needs replaced.
Replace the 2014 OEM thermostat with a 2015-2019 OEM thermostat. The 2015 & up thermostats open ~10-15 degrees earlier than the 2014 and since the cooling system has the needed capacity, the coolant temp will be lower. New OEM thermostats are on RockAuto. Very easy to change. 1000 threads on how to do that.
Replace the 2014 OEM thermostat with a 2015-2019 OEM thermostat. The 2015 & up thermostats open ~10-15 degrees earlier than the 2014 and since the cooling system has the needed capacity, the coolant temp will be lower. New OEM thermostats are on RockAuto. Very easy to change. 1000 threads on how to do that.
A thermostat sets the lowest temperature that your engine will run at. For example, if the thermostat installed is 190F, the engine temp should remain at 190F or greater. On the other hand, a 170F thermostat will not drop engine temperature if the engine temperature is at 230F.
A thermostat sets the lowest temperature that your engine will run at. For example, if the thermostat installed is 190F, the engine temp should remain at 190F or greater. On the other hand, a 170F thermostat will not drop engine temperature if the engine temperature is at 230F.
Thanks for saying exactly what I said.
The 2015 & up thermostats have a lower opening temp than the 2014 thermostat. Use a 2015 & up thermostat and run at the lower tempsince the cooling system has sufficient capacity to do so or continue to use the 2014 thermostat that opens 10*-15* higher and run at a higher coolant temp since the 2014 thermostat is forcing that to happen by opening later.
The top tune is stock. The bottom tune I changed the values.
The $600 solution to the $100 problem Of course if the OP is going to do more to the car then I do agree....totally worthwhile .
Having said that...With the higher opening point of the 2014 thermostat, a programming change is going to be pulling air through a radiator that has reduced coolant flow due to the closed thermostat. It slows the temp increase more than stops it although if it's cool enough outside, it can help. To really take advantage of the programming, thermostat needs to be changed. Now you have a lower opening point and the fans running to keep it there. The 2014 cooling system is the same as 2015 so it has plenty of capacity (for a street car).
To the OP....lots of threads from 2013/2014 when the C7 was introduced regarding people not liking the higher temps. There are more threads from 2015/2016 once it was discovered that GM used a cooler thermostat for the 2015 & up cars with no other changes and that those cars tended to run 10* or so cooler under the same conditions.
To the OP....lots of threads from 2013/2014 when the C7 was introduced regarding people not liking the higher temps. There are more threads from 2015/2016 once it was discovered that GM used a cooler thermostat for the 2015 & up cars with no other changes and that those cars tended to run 10* or so cooler under the same conditions.
So there were no programming changes in the ECM programming WRT the fans? IDK since I didn't tear apart the programs. Was it changed for some reason? I doubt GM changed it just because a few people were unhappy. Could it have anything to do with the A6 to A8 transmission change? I could see them doing it to standardize parts once the A8 came on line? Just a thought.
Did anything improve with the thermostat change? Performance? Emissions?
So there were no programming changes in the ECM programming WRT the fans? IDK since I didn't tear apart the programs. Was it changed for some reason? I doubt GM changed it just because a few people were unhappy. Could it have anything to do with the A6 to A8 transmission change? I could see them doing it to standardize parts once the A8 came on line? Just a thought.
Did anything improve with the thermostat change? Performance? Emissions?
Don't really care. Bottom line is they made changes. Feel free to research......
If you want to dive into the programming....
And if you want to dive into the details I can attach some 2014 & later OEM files to compare. The below shot is the base 2014 file vs a 2019 file. Green is where GM made changes. 2014 values are shown. Grayed box means the 2019 file doesn't use this parameter. Lastly I will mention that not all parameters apply. You have to look at each one and decided if it does something or if it's an artifact in the programming for other vehicles since at least some of the base parameters are for items the Corvette is not equipped with, such as a switched water pump.
They're as low as $375 for MPVI3. It's totally worth it. They're so many things you can do with it. Changing the fan speed and thermostat to a 160, and disabling DOD was one of the first thing I did. One of my favorites is customizing the exhaust NNP valves. The valves can be programmed to open and close, in any gear, at any rpm and engine speed.
Probably not going to tear apart the programs. Way too much for a "one off". I leave the programming to others who do it for a living. I'm not too proud to ask them their thoughts.
They're as low as $375 for MPVI3. It's totally worth it. They're so many things you can do with it. Changing the fan speed and thermostat to a 160, and disabling DOD was one of the first thing I did. One of my favorites is customizing the exhaust NNP valves. The valves can be programmed to open and close, in any gear, at any rpm and engine speed.
Now add in the cost of the credits. For the PCM and TCM it’s 6 or 7 as I recall. $50each. Just buying for the PCM is $200 so there you go.
Based on the question, I doubt the OP will be diving much into tuning to justify the $600+ total cost.
Fan Activation
Of course if the OP is going to do more to the car then I do agree....totally worthwhile 
.
