wierd AC problem

[strad]

Ok. We know the charge is right. We know the compressor is working normally, as ascertained with high and low side pressure gauges. We know the rear AC blows cold just fine. But the front AC is not blowing cold.

What would be the possible causes of that? This is a 99 Tahoe in case it matters.

 

[SunlitComet]

dirty evap effecting efficiency, a temp door not working properly or an orifice tube problem.

 

[t3amcha0s]

same issue on mine. but if i have the rear ac on at the same time and same fan speed it seems to work

 

[SunlitComet]

you mean the front suddenly starts to work better when you turn the fan on the rear one on?

 

[t3amcha0s]

yes! i know it makes no sense at all

 

[SunlitComet]

makes perfect sense. either you have the wrong charge in it or you have a problem with the plumbing or orifice tube for the front system. the front metering is not adjustable and has a fixed metering hole but the rear uses a "self-adjusting" metering device. http://en.wikipedia.org/wiki/Thermal_expansion_valve.
when the rear valve is changing you are effectively changing how the front reacts under giving circumstances. hard to explain in easy terms.

 

[t3amcha0s]

yeah i understand what ya mean i have to get it fixed soon texas summer is brutal