Hello, need help.......duh......I wanted to check and charge the A/C and I can not seem able to find the low side port. Of course while I was looking I came across two things I need help identifying. One pic will show a black plastic slotted cap. It has a huge spring underneath. Arrow pointing to it. Can someone tell me what that is? Next picture is me holding what appears to be a vacuum line that goes to nowhere..........Much appreciation in advance if anyone is able to educate me on this. Thanks.............and yes I'm still searching for the low pressure port on the A/C......I'm sure it's buried in there somewhere.

 

Does that vacuum line go to the egr valve? I think I see it buried under there and there should be port on the top it would connect to. There should also be a sticker on the hood with a vacuum diagram.

 

In your photo looks like the port is directly behind the white zip tie bundling up some of the vacuum lines

 

my bad that's not the egr by the way.

 

Thanks for the replies.........It's storming here right now so I'll take a look tomorrow. Nothing about the black plastic cap with the large slot cut into it?

 

The slotted spring loaded black thing is the A/C idle up adjustment screw. It's gives the engine a little RPM boost when the A/C kicks on so it doesn't bog down at idle.

 

Thanks for that info. I looked through the shop manual and couldn't find it at all. In my search for the low pressure A/C port I unscrewed it thinking it was a cap for something. Of course it's not. It's got a long stem that screws back into the housing. I screwed it back together but I have no clue where it should be adjusted. Is it something I can turn the A/C on and adjust with my ear? Or is there a more scientific way to adjust it properly? Thanks again.........

 

Like Robert m said ,it is the A/C idle up valve. It adjusts your idle speed when the A/C is turned on. So at idle turn on your A/C and adjust it using your tach if you have one or by ear if you have to. Without it, your engine will lug down at idle with the A/C on.

 

The diaphragm behind the white zip tie is the PAIR valve. http://web.archive.org/web/201311071...78pulsedse.pdf If your vacuum lines are factory, and your loose line is labelled "#4" (it looks like it), then they go together.

On my truck the low-side port is right next to the high-side port at the firewall.

If you don't have a low-side port there, the next place I'd look is on top of the compressor.

 

I wish mine was that easy to see and get to. I did find it. It was hiding behind the black tubing in the pic. Thanks for your help.

 

Thanks for that. Yes, my truck has a tach. When I started the A/C the tach actually went up 200 RPM.......Guess I need to adjust the screw to back it down a bit? Thanks again....