I have a 2003 G35 Sedan, which has only one electric condenser fan. The fan does not spin when I turn on the car. In fact, it only kicks onto HIGH setting once the car starts to overheat. The mechanic told me that once I replace the fan assembly it will run fine; however, if the fan spins at HIGH and not LOW, this leads me to believe it's an electrical issue. I tried turning on AC and it still did not kick on until it started to overheat.

Any help would be deeply appreciated!

 

Not sure about the 03, but on my 06 the relays for the fans are in the IPDM and those control when LOW and HIGH are turned on/off. My motors also have four wires in each and if you apply power/ground to two of the correct wires it will run in LOW. If you apply power to two wires and ground to the other two wires it will run in HIGH. If your motor is similar and you do disconnect them and test them that will let you know if LOW setting works on the motors and then you are left with either a relay or the wiring.

 

Thanks for the reply! My 03 sedan only has 1 cooling (condenser) fan, however I'm sure the testing process is similar to yours. I will try this tomorrow! Thanks again!

 

There are 3 relays in the IPDM that control the fan speed, one of them is probably failing, label them 1, 2, 3 with a sharpie then swap them around. You can test for high speed by turning the AC on while the car is running, that forces the fan speed to high. I'm betting you should be able to swap relays around to a configuration that will NOT allow the fan to kick on to high speed.

If so then just replace all 3 relays with new ones.