1998 Chevy Suburban ac problems

Rear AC not blowing air

So...the fan does not work? Or does it not blown cold air? If the fan works, you need to check the a/c pressures. Low charge will cause this.

I tested the fan directly & it does work, i replaced the relay & it still doesn't work, i check the power but there is no power going to the fan so i checked the ac switch & there is power going to the switch, i really don't know what else to replace

I tested the fan directly & it does work, i replaced the relay & it still doesn't work, i check the power but there is no power going to the fan so i checked the ac switch & there is power going to the switch, i really don't know what else to replace

since you applied 12volts to the blower motor and it works also the blower when hooked up normally does not work in any position I would re check all fuses. check for power to those fuses as well.

Does the rear blower work for heat?

Shouldn't there be a separate pressure switch for the rear system? If the refrigerant is low, you may not have enough pressure to fire up the rear system.

No the heater doesn't work either i changed the porportion value but nothing only thing i need to replace is the ac switch

If the rear blower doesn't work for heat either, it has nothing to do with the AC pressure switch. Sounds like one of the fan switches, or diode pack if separate, is bad.

I have a 95, might be the same. I dont even turn the ac on anymore. It quit blowing in the rear like dust and crap was stopping the right vents from opening up. Then someone else told me it's some hell getting to that stuff, so I forgot about it. Had already switched from some old coolant to some new ac coolant, they put something in the lines. Cost me more to recharge the system the very next year, cuz thats what they said would fix that no blowing cold in the back. None of that worked, old bastard truck likes to blow the odd belt, Alt gauge is whacky. Running a 6.5L diesel, runs hot as it is, AC used to always just make it run hotter. I gave up. But search here for more info about those rear vents, there is a good chance I read it here.