just replace place fan assembly on g35 2005 low side works but no high speed fan it blows ice cold air out ac and not over heating even being in fla weather i have power at the fuse box and fuse 40a is good but no high speed fan

 

If the A/C switch is off the high speed won't turn on until the temp reaches 212.

A/C switch on < 50 MPH and A/C PSI < 229.1 the high speed will not turn on until 212 as well.

If A/C switch is on at any speed and the A/C PSI > 229.1 it turns on high speed all the time.

There is an refrigerant pressure switch that could possibly go bad I guess.

There are also 3 relays in the IPDM box and all three of those have to work in order for the fan to run at high speed.