overheat
Thread Starter
Racer
Joined: Jun 2005
Posts: 289
Likes: 10
overheat
Got a real one here. 2009 zo6. Modified with 636lift cam, headers nw 102. This car has had overheating issues. I have jumped the wires at the connector to the fan module control and i start the fans sometimes. When they come on they only run for a short period of time, like when I start the engine. Then the fans turn off. have relaced temp sensor, fan control module, had the coolant replaced and vacuumed to removed all air in the system. It seems as the ecm is shutting off power to the fans when engine is warmed up. Before I bypass the entire stock system has anybody ever encountered this type of problem?
Any Ideas what is causing this? Could the ecm have a fried wire? Can the RF system cause this failure? I am totally frustrated. Mark
Any Ideas what is causing this? Could the ecm have a fried wire? Can the RF system cause this failure? I am totally frustrated. Mark
Last edited by jazzmk1; Apr 12, 2022 at 03:26 PM.
Thread Starter
Racer
Joined: Jun 2005
Posts: 289
Likes: 10
overheat
it did melt the wiring, it has been replaced with new. connectors as well. it seems as the ecm is providing power to the fan control module. I think the control wire has burned inside the ecm. I just wanted to find out if anybody else has had this problem and if it could be fixed without buying a new ecm and need for a retune. I don't really want to spend that much money but if need be i will. The fan control module does not have power at all times very sporadic i would say..
Last edited by jazzmk1; Apr 12, 2022 at 09:57 PM. Reason: adding info
Race Director
Joined: Dec 2013
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it did melt the wiring, it has been replaced with new. connectors as well. it seems as the ecm is providing power to the fan control module. I think the control wire has burned inside the ecm. I just wanted to find out if anybody else has had this problem and if it could be fixed without buying a new ecm and need for a retune. I don't really want to spend that much money but if need be i will. The fan control module does not have power at all times very sporadic i would say..
No, the ECM control wire is a grounding wire, and controls the PWM via the amount of ground resistance it sees.
As for PWM, it sending power to the fan full time, and its the PWM/fan ground wire to the frame chassis, that is being controlled for the pulse width to control the speed of the fan.
So if you ground the ECM control wire to ground for the PWM, it should have the fan off full blast.
If this is not happening, then check the PWM ground wire and connectors.
If connectors and ground wire is fine, then either PWM or raditor fan is burnt up.
Note, C6 Oem radaitor fan is a bushing fan, so with the fan over run via lowering the temp Control tables, its is possible to either burn the fan brushes out, or burn the bearings up instead.
Stock fan table settings,
Attachment 48335485
As for if you did burn up the PWM by over taxing with the fan tables way lowered, then screw trying another PWM, and time to just switch over to a 20 amp SSR that can take the abuse instead.
https://www.corvetteforum.com/forums...ring-help.html
Last edited by Dano523; Apr 12, 2022 at 11:47 PM.
Thread Starter
Racer
Joined: Jun 2005
Posts: 289
Likes: 10
A quick update...I did find one of the ground wires had some corrosion or something like that , the wire had a black substance throughout. So I just bypassed the entire factory system, and now the fans are on a on/ off switch. I am looking to find put a stand alone system in place.
Race Director
Joined: Dec 2013
Posts: 12,500
Likes: 3,625
A quick update...I did find one of the ground wires had some corrosion or something like that , the wire had a black substance throughout. So I just bypassed the entire factory system, and now the fans are on a on/ off switch. I am looking to find put a stand alone system in place.
Lost here, since ECM should be using the engine temp sensor (in drivers head front side) to control the PWM from the engine heat, as well as turn on the fan when the HVAC system is turned on, so I that part of the system is working, then just a mater of updating the Stock PWM that may be cooked, with SSR that can take the abuse isntead.
If the problem is that the cooling system (fan and radiator) can not keep up with the cooling tasks when the fan is running full blast, then they should be replaced with units that can isntead (dual fan set up, better cooling radiator, and SSR that is amp sized for the dual fan power requirements).
Hence still not a bad idea to allow the ECM to control the system, since as stated, still need to turn on the radiator fan to draw air through the condenser when the HVAC system is on, and not reason for the fan to be running when the engine is cool, with the fan just taxing the charging system instead.
And again, ECM controls the negitive control side of the PWM, with resistance to ground as the factor.
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