When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
Hopefully this is the right place for this, I have a new to me 07 1lt… the previous owner said the radiator fans were hard wired and would run non stop, he installed a gspeed radiator fan kit, and now they don’t run at all…. Is there a way for me to force the fans to run via switch on the g speed? Or do I need an ecm replacement…I tried disconnecting the green wire on the second plug and grounding it out to see if the fans would run I even tried applying 12v to see if it’d run… and nothing… thanks for help in advance
Hopefully this is the right place for this, I have a new to me 07 1lt… the previous owner said the radiator fans were hard wired and would run non stop, he installed a gspeed radiator fan kit, and now they don’t run at all…. Is there a way for me to force the fans to run via switch on the g speed? Or do I need an ecm replacement…I tried disconnecting the green wire on the second plug and grounding it out to see if the fans would run I even tried applying 12v to see if it’d run… and nothing… thanks for help in advance
Well if you put 12v right to the fan i think your fans are toast. Burn out from going full bast all the time. It was just coincidence . JMO
That's how i figured out one of my fans burnt out. Car started to run hot.
Well if you put 12v right to the fan i think your fans are toast. Burn out from going full bast all the time. It was just coincidence . JMO
That's how i figured out one of my fans burnt out. Car started to run hot.
they’re new g speed fans and i don’t think they’ve ever run, I’m not sure if the signal wire is sending signal to run the fans, which is why I’m asking if there is a way to function test the g speed fans
how are they wired up? If youre partially using the C6 system, just be aware the C6 system is PWM based and uses the ground side to pulse on and off..?
If you want simple, can you just wire up a thermostatic switch to a ignition powered relay and have it directly drive the fans? if you hook up 12V to the gspeed does it turn on?
* CONFIRM THAT ECU FAN CONTROL HAS NOT BEEN ALTERED. SETTINGS HAVE TO ALLOW FAN SPEED TO BE CONTROLLED AS INTENDED FROM THE FACTORY. TEMPERATURE SETTINGS CAN BE ADJUSTED. *
how are they wired up? If youre partially using the C6 system, just be aware the C6 system is PWM based and uses the ground side to pulse on and off..?
If you want simple, can you just wire up a thermostatic switch to a ignition powered relay and have it directly drive the fans? if you hook up 12V to the gspeed does it turn on?
the g speed fans run a power wire directly to the fuse box and then a power to ground and use the stock geeen wire for signal
the g speed fans run a power wire directly to the fuse box and then a power to ground and use the stock geeen wire for signal
Honestly, I think you have to take it back to stock control. this is a brushless fan so it sounds like it needs some PWMing to control the fan. 12v direct may just electromagnetically lock it in place? Not 100% sure sure how brushless works but i believe the controller needs to send power to the different wire loops to connect/disconnect the magnetic field to rotate the shaft (???? not an electrical engineer, correct me if im wrong). If the gspeed wants stock control, it may have a brushlses controller built in, waiting for the PWM pulses
Honestly, I think you have to take it back to stock control. this is a brushless fan so it sounds like it needs some PWMing to control the fan. 12v direct may just electromagnetically lock it in place? Not 100% sure sure how brushless works but i believe the controller needs to send power to the different wire loops to connect/disconnect the magnetic field to rotate the shaft (???? not an electrical engineer, correct me if im wrong). If the gspeed wants stock control, it may have a brushlses controller built in, waiting for the PWM pulses
yea it’s brushless I bought it like this so I might just bite the bullet and buy a stock style radiator fan
yea it’s brushless I bought it like this so I might just bite the bullet and buy a stock style radiator fan
If all the stock control plug is there, the controller itself is like $80 or so...Cant find the gspeed wiring diagram so i dont know if they want you to pull signal from the controller or the plug that goes to the controller...
If all the stock control plug is there, the controller itself is like $80 or so...Cant find the gspeed wiring diagram so i dont know if they want you to pull signal from the controller or the plug that goes to the controller...
the way it’s set up is the green wire was cut and spliced to a standalone plug that ties into the plug that powers the fan
Last edited by Paulmg1986; Jan 31, 2026 at 05:57 AM.
The brushless is controlled by the little thermostat thing that goes into the hose or radiator (no box very small). Say you have a range of 175-195 controller it comes on in 3 equal parts 175, 185 and full on at 195. This is my Dewitt brushless fan. Depending on your fan plug situation you might want to upgrade to the Metripak 600 to the Metripak 800 it can take almost double the current (see photo for differences).
The brushless is controlled by the little thermostat thing that goes into the hose or radiator (no box very small). Say you have a range of 175-195 controller it comes on in 3 equal parts 175, 185 and full on at 195. This is my Dewitt brushless fan. Depending on your fan plug situation you might want to upgrade to the Metripak 600 to the Metripak 800 it can take almost double the current (see photo for differences).
here is what it looks like, also I just disconnected the coolant temp sensor and fan did not kick on, and they do spin freely
Last edited by Paulmg1986; Jan 31, 2026 at 11:53 AM.
You are getting a lot of bad advice about this fans operation. This is a Spal brushless fan (same style as the C7 and up Corvettes). The controller is built into it. Its' operation is similar to the OEM C6 fan except than the fan controller being built in verses the C6 fan which had a separate controller. If you put 12volts to the large red wire and ground to the large black wire......nothing will happen. This type of fan needs the PWM wire (white small gauge wire) hooked up to the C6 Corvette ECM PWM wire to function.
The other small wire from the fan(yellow wire) is not connected. This fan/shroud is sold by Dewitts 32-SP480. It requires a 50amp fuse on the red power wire.
You are getting a lot of bad advice about this fans operation. This is a Spal brushless fan (same style as the C7 and up Corvettes). The controller is built into it. Its' operation is similar to the OEM C6 fan except than the fan controller being built in verses the C6 fan which had a separate controller. If you put 12volts to the large red wire and ground to the large black wire......nothing will happen. This type of fan needs the PWM wire hooked up from the C6 Corvette ECM to function.
The other small wire from the fan is not connected.
the green wire is connected from the engine harness to the fan via connector, I’m going to order a Casper switch and see if i can force it on
I presume your C7 fan is plugged into the hot lug by the fuse box there and is grounded to the frame somewhere. There should be an in-line fuse or something there to protect it. Can you see if that is in good shape and not blow or tripped?
I presume your C7 fan is plugged into the hot lug by the fuse box there and is grounded to the frame somewhere. There should be an in-line fuse or something there to protect it. Can you see if that is in good shape and not blow or tripped?
2007 c6 radiator fan issues
