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Air Conditioning:2005 Passat

8K views 5 replies 5 participants last post by  Steve in Chicago 
#1 ·
HELP PLZ! Air Conditioning Prob:2005 Passat

Hello,

I'm been having difficulty with my Air Conditioning in my 2005 Passat 1.8T. It is just blowing warm air or air that's the same temperature as outside. Sometimes it will all of a sudden come on in the middle of driving, and stay on, until I turn the car off, but this happens rarely now. I'm wondering if this could be a problem with the AC Unit's Compressor relay switch. I never hear the compressor kick in. It does only during those rare moments. The low pressure reading was in the red zone according to the refill canister I used. @ 110psi. Could this be too high and causing the AC Compress not to kick in? Or could it possibly be a compressor relay switch issue?

Any suggestions would be greatly appreciated!! thank you!

-Kevin
 
#2 ·
While you may or may not have compressor switch issues, you cannot trust the 25-cent gauge on the can to fill the B5 A/C. You can't even use real refrigerant gauges on it, due to some quirk with the compressor design.

The only way to get the A/C properly charged is to properly evacuate the system, draw a vacuum while you are at it to check for leaks, and fill it with a weighed charge.

SirWired
 
#4 ·
If your system has lost charge, yes, you should assume there is a leak. However, there have been anecdotal reports here that some Passats were under-charged at the factory, but take that with the proverbial grain of salt.

SirWired
 
#6 · (Edited)
I never hear the compressor kick in. It does only during those rare moments. The low pressure reading was in the red zone according to the refill canister I used. @ 110psi.
You need to have the compressor running to get a useful reading of the suction side of the system. R134a will produce about 110 psig at 93ºF. If the compressor isn't running, the system will equalize and you'll see the same pressure on both sides of the system.

while idling i get no cold air, only when i am moving does it blow cold.
Check to be sure the electric fan on the radiator is turning on when you turn the A/C on. If that's not your problem, have the refrigerant charge checked.
 
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