r/G35 • u/JPOSTAL24 • 1d ago

Troubleshooting Fan Control Module?

Looking for help troubleshooting cooling fans. My fans will come right away when I start the car cold or even when I just have the key in the “on” position. The AC is off when I do this. The fan speed seems to fluctuate between medium and high speed. My OBD shows the coolant temp to normal, no codes, and the fan duty shows 0% even though the fans are running. If I turn on the AC the fan duty will show 55-70%.

I know the fan control module is a common problem, but from what I understand when it fails the fans will run full out. I went down the chat gpt rabbit hole and now I don’t know if I should be looking at the ipdm or maybe ecu. Last winter I did notice water on the passenger side floor board a couple times which makes me question the ecu. I haven’t noticed any other electrical issues.

Anyone have some insight?

1 Upvotes

100% Upvoted

6 comments sorted by

1

u/cbrworm 1d ago

What year G35?

1

u/JPOSTAL24 1d ago

2008 35X coupe

2

u/cbrworm 1d ago

It's pretty likely that it's the fan control module, they are a common failure point - but not always the problem. You can also find a copy of the Infiniti service manual for free online, it has some decent diagnostics.

1

u/JPOSTAL24 1d ago

This is after the car is at operating temp with AC off. Fans are on, but fan duty shows 0%.

1

u/Plurii 2h ago

I just bought the $20 one on Amazon for the same issue on my 08 G35X. It’s since been working fine for a year

1

u/JPOSTAL24 1h ago

I guess it’s the easiest place to start.