View Full Version : Sub Fan Radiator Motor
waruaki
05-15-2014, 10:48 AM
Is it necessary to connect the radiator sub fan? I have the primary number one fan connected but can't tell if the sub fan will even function with all the air conditioning components removed? Any body know if it also activates also when the engine temperature requires the primary fan to come on?
Thx
Good question, I hadn't thought about that and I'm in the middle of my wire harness diet.
Looking at the manual; Both fans operate at the same time under the same conditions. Both fans will operate at a low speed with temps over 205. Both fans operate at a high speed when the A/C is turned on. It looks like you could delete the second set of fan relays and associated wiring, but you need to keep both fans.
Bob_n_Cincy
05-15-2014, 12:40 PM
In mine, the fans run in series for low speed. (6 volts each) when fan relay 1 turns on.
Then runs in parallel for high speed (12 volts each) when the fan mode relay and fan relay 2 turns on.
Bob
longislandwrx
05-15-2014, 04:04 PM
You can adjust how the fans function with the ECU. I would install them both and worry about it later.
waruaki
05-16-2014, 10:38 AM
You can adjust how the fans function with the ECU.
Feel free to give a detailed, step by step guide on how to do this? I'm sure I'm not the only one who would like to know how to re-flash the ECU to "adjust how the fans function"
Thanks for the explanation Rori, Bob and Cindy. It's appreciated.
sponaugle
05-16-2014, 12:05 PM
Feel free to give a detailed, step by step guide on how to do this? I'm sure I'm not the only one who would like to know how to re-flash the ECU to "adjust how the fans function"Thanks for the explanation Rori, Bob and Cindy. It's appreciated.
He was referring to having your ECU reflashed by either using the open source Rom Raider, or getting a Cobb AP. Both of those solutions can adjust some of the fan functions.
There is no single step-by-step guide as it is different for different ECUs. Most of the 16 bit ECUs have one method, and most of the 32 bit ECUs have another ( pre 2008 that is ).
A quick bit of googling can bring up a few good explanations of how to adjust them with RomRaider, and equally you can do the same with the Cobb AP.
http://www.romraider.com/forum/viewtopic.php?f=3&t=9646
http://www.romraider.com/forum/viewtopic.php?f=7&t=1868
Jeff
longislandwrx
05-16-2014, 12:53 PM
Thank you Jeff.
I had actually started typing up how rom raider or Cobb Accesstuner Race could be used to do this, but It started going off topic so I simplified the answer.
No need to be snarky... I was just trying to help by saying yes, I would install the second fan, and if its not doing what you want, you can adjust it later. Jeff pointed you in the right direction with the RR, I haven't looked in a while but I believe Cobb has two radiator control tables you can edit, which toggle output values:
Radiator Fan Relay #1 Switch >
Radiator fan relay #1 status as determined by the ECU. Value is ON when the
ECU determines that the relay should be on.
Radiator Fan Relay #2 Switch >
Radiator fan relay #2 status as determined by the ECU. Value is ON when the
ECU determines that the relay should be on
I haven't looked at it recently but iirc you can link these outputs to additional conditions.