So if I sit for a while the G will start boiling coolant and the gauge shows HIGH. One fan is turning barely the other fan does nothing. Both spin freely when the car is off which bothers me because usually they would seize if bad.

OBDII doesn't pull any codes but I don't have a live scanner.

Do these fans work on 12V? I'd like to check them before getting new ones.

What is the output voltage from the harnesses when operating in Lo/Hi? The service manual doesn't specify.

THX,

G

 

All the information is in the FSM


http://www.nicoclub.com/FSM/G35/Seda...5_Sedan/co.pdf

See page CO-06

Cooling fans are controlled by ECM. For details, refer to
EC-488, "
DTC P1217 ENGINE OVER TEMPERA-
TURE
"

http://www.nicoclub.com/FSM/G35/Seda...5_Sedan/ec.pdf

Cooling Fan Relay Operation
The ECM controls cooling fan relays in the IPDM E/R through CAN communication line.

You may want to consider not only replacing the fans but the thermostat, water pump, radiator cap, and flush the coolant. Might be time to replace belts and hoses while you are at it?

Good luck

Telcoman