Climate Control Question

[Jeff B]

Hey guys,
I have an 87 GN. My question might be stupid to some of you, havent really been able to find the answer. I have the manual climate control with the sliding lever. Can anyone give me the functions of each option? What i mean is, it has for example under the box for AC is says "Max, Bi-Level, norm", then has the economy box that says "heat, vent", then has the defrost option. The reason for my question is that i had been experiencing some low fuel economy in my opinion. Since its been warm out ive had the lever slid all the way to the left on cold and the other lever on Bi-level. Now my ac is in place but not charged (so doesnt refridgerate the air). What im asking basically has this been causing me to have lower mpg do to the ac pulley being engaged? Additionally if anyone can give me their best description (preferably whatever it says in the owners manual) of the different settings, id really appreciate it!
Thanks,
Jeff

 

[jopaustu]

Jeff, your compressor should not be engaged if there is no refrigerant in system. Pressure safaty prevents this ,unless it has been bypassed. That would not be good.... on the vent mode there is an intake on top of the evap. Plenum.. below the passenger side wind shield . This will let a portion of outside air in. Not sure what other modes allow that valve to open though. I don't think the a/c when working, noticeably kills your fuel economy.definetely not when its not working.