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Identify AC High Side vs. Low Side

Can you Identify AC High Side vs. Low Side?

Identify AC low side of the system where the freon goes is always the fastest of the two hoses coming off of the compressor…

If your A/C stops blowing cold air several days, weeks or months after you recharged it, it means the system has a leak and the refrigerant is escaping. You should add some leak detection dye to the system to find the leak. The leak should then be repaired before the system is recharged again, otherwise, you are just wasting your time recharging the system over and over again.

MVS Forum Member MattElmore says:

The compressor on my girlfriend’s Volvo has a slight leak in it and needs to be recharged every 6 months or so. Hopefully she’ll have the money to replace the compressor at the end of the summer ($1000 job), but for now we’d like to recharge so she can have some air.

I can find the recharge valve on my Toyota fine, but I’m unable to find it on her car.

If someone can help me out I appreciate it. I have to drive around in the car sometimes too and it sucks with it being 95 outside with no air and leather seats! 😯

MVS Forum Member A.Baker adds:

Here is a quick way to find ANY charge port on ANY a/c system.
The low side of the system where the freon goes is always the fastest of the two hoses comming off of the compressor. The high side of the system is the smaller of the two. And on a 134a system the low side port is the bigger of the two. Hope this helps.
A. Baker

identify AC

Identify AC High Side vs. Low Side


what sequence of testing should I use to find out why the compressor is turning on. Relay, recharge. pressure switch?

The 2000 v70XC only has a low side which is on the passenger side and has a cover on it.NO High Side.

Leo Blumle says:

The connector that is on the charging hose you get at every auto parts store ONLY fits on the low side. DO NOT EVER CONNECT INTO THE HIGH SIDE ESCEPT WITH THE SERVICE GAUGE SET THAT HAS TWO PRESSURE GAUGES ON THE VALVE MANIFOLD

linda miller says:

have car in shop – tech can’t find high side. Any clues beside knowing wich is the smaller line? Volve 850 1996

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