My 2004 Suburban 2500 has front and rear air conditioning. I want to check the R134A pressure, but can only see two ports that are on the high side. Does anyone know where I can find a low side port? Any help would be appreciated.

Thanks,

rjoenga

 

High side is the larger of the two ports,there is an orifice between them in the line(find out where the hot stops and cool begins-thats where it goes from a high temp high pressure liquid to a low pressure low temp gas).

Only real way to know is suck out the freon and put back exactly how much goes in it(3lbs in my '03 Sub with front and rear a/c). That would need to be done by a professional. There's a label on the fan shroud that tells how much it takes.

 

Welcome to the forum. You can get a set of refrigerant gauges and check the pressures. Then check this: http://www.id-usa.com/pdf/GBM-2CS_E.pdf This should get you in the ball park.