Where should my fan setting be for a/c recharge

Does it matter if my fan setting is on “high” or “low” when I fill up my car’s A/C ? The literature typically says “Max A/C” but never specifies fan settings.


You want the fan speed on high when recharging the A/C system. This allows you to measure the vent temperatures as the A/C is being recharged.


“Max A/C” always means with the fan set to high. Most cars default to high fan if they have a “Max A/C” button or setting.

Off ? You must be drunk.

Thanks! Very helpful.

Not only do you want your evaporator fan settings on high, you also want to make sure the condenser (Radiator) fans are operating. Refrigerant constantly changes properties from a gas to a liquid as it circulates through the system which affect the high and low side pressures. When charging any refrigeration system, whether it be automotive, home A/C, or commercial refrigeration units, the compressor is on, and the condenser and evaporator fans are on.


As long as the compressor is running and so are the condensor fans are also running it makes no difference.Charge by weight,observe pressure reading,steady,not to high,not to low.If you do want to measure outlet temp GM does recommend center outlet car in shade 2000rpm blower on high.For me the key to no come-backs was charging the correct amount of refridgerant.In any technical schooling I have had GM Dealer Training,Community College courses,ASE Certs. it was never asked and my practical experience showed it did not matter.