I have an 06 G35 Coupe with an odd climate control issue that I have been tryng to solve. If the temperature outside is below 45 degrees or so, then the heat and A/C will take at least 25 min of driving before the fans start up. This happens both in automatic and manual mode for the climate control. The display will actually show the fan speed increasing when in automatic mode as the car warms up but the fans dont spin until almost exactly 25 min. every time. This is after both city and highway driving. The car gets up to operating temperature fine and you can even feel the heat radiating from the vents while driving. I have made sure that there is enough coolant and that the system is bled. What really confuses me is that when the outside temperature is warmer, I do not have this issue. I understand cars need to heat up before the HVAC kicks on but a minimum of 25 min. before it does is definitely way too long. Any help with this would be greatly appreciated.

Check out the troubleshooting steps in the FSM

https://www.nicoclub.com/service-manual ... 06/atc.pdf

See page ATC-98

I'm quite sure you would be able to obtain a quick answer by spending the one hour diagnostic fee at your local Infiniti dealer? The Consult tool that they use would most likely give you the root cause of your issue?

I went through the FSM and the diagnostic mode and everything appears to check out through there, no errors. I am hoping to avoid the dealership and do this myself in hopes of saving some money. The main thing that confuses me is that this only happens when it is cold outside and will not work unless I start the car on a warm day. I cant even get cold air to blow through when it is cold outside, even with the engine at operating temp. Normally I would point towards the blower motor but it works fine on warm days.

This is a weird one. I'm gonna suspect a bad air blend door actuator.

When you say "the fans," I assume you mean the blower motor?

You can hear the blend door moving when you change the temperature with the dial and it works fine as well when it is warm outside. and by fans yes I did mean the blower motor. It's weird too because the climate control display will show the fan speed slowly ramping up as the car gets up to operating temp (like it is supposed to do) but the blower motor never kicks on.