How do I locate the low pressure port in my 2008 hummer h3

I can’t seem to find the low pressure port on my Hummer H3. Can anyone help?

Are you trying to add refrigerant to your AC system? If so…have a knowledgeable mechanic or friend show you where it is. In my opinion…you should take the H3 in to an independent AC shop since you obviously have a leak if the refrigerant is low. Simply adding refrigerant is not a repair.

Though I am not an a/c man, when a cousin’s Yukon needed Freon added here in Mexico, I did a lot of searching on the Internet. For best service, it is recommended first to fix the leaks, then to take out the Freon, and fill again by weight. I went up the hill to tell him. He had added some, and it completely stopped working. So, I assume the pressures got too high and blew something out in the system. Cheaper to do it right the first time.

If the A/C is not working that does not mean the system refrigerant charge is low. Maybe there’s a compressor or cutout switch issue, blend door problem, etc, etc.
Maybe even something as simple as a blown fuse or fusible link but the first step is determining whether or not the compressor is kicking on.

Just a warning, but refrigerant can be dangerous if mishandled. Frostbite in 2 seconds, blindess, and breathing problems are some of the dangers if you get bitten so to speak.

Thanks for all your input> Much appreciated! Sometimes the air works and sometimes not. Does that mean it needs to be charged?

If the system sometimes blows COLD air out the vents it is not likely that adding refrigerant will fix the problem but you still need to connect a high and low side gauge and check the running pressures. At the firewall there are 2 AC lines. One is the high side and runs to the condenser. The other is the low side and runs to the compressor. The low side service port is on the low side line.

Thanks Rod. Yes sometimes it works fine and blows REALLY COLD air, so I guess I need to get it checked out by a pro. I also have added coolant to my previous vehicles and it was simple. However on my H3 I can’t for the life of me find the low port. I think it may be enclosed. Usually the blue cap is visible but not on this thing. again thanks for your input everyone!!

I am not familiar with the Hummer but the low port will certainly be in the hose from the firewall to the compressor and on rare occasion I have found it necessary to go from under the vehicle to connect the gauge. Some are at the compressor low side connection and are very difficult to access. An independent AC specialist is often the best place to go for peculiar problems.