I need to find the low side ac service port for my 2000 dodge 3500 ram van so that I can add refrigerant. Determining the proper port has proved very confusing based on where you read in the internet!

I bought a Quest "re-chill kit" that has the gauge and hose. It would appear that the gauge fits/screws on directly to the can of refrigerant, while the hose leading from the gauge/screw fitting is what must be attached to the low side service port (the fitting here is not threaded). However, this is the*larger* of the two fitting on the gauge/hose. This would only fit on the larger of the two ports I seem to be able to find, but most people seem to suggest that the larger port is the high side port and not the low side port.

I have taken a photo that shows both ports. I can't seem to get it to post here, but here is the link:

https://picasaweb.google.com/lh/phot...eat=directlink

You can see the two ports/plastic caps there. The one on the right is the larger port, the one on the left is the smaller port.

I think my van is set up a little differently than what I've been able to find so far. Anyway, if someone can help me with this, that would be great! Don't really wanna blow up a can of refrigerant, or myself.

 

Low is on the left and the High is on the right.

Did you actually try and connect to the low side fitting yet?

 

The ports for R134a systems are different sizes, so it is not possible to connect a refrigerant can to the wrong (High) side.

 

Hooked up to the low side fitting and have emptied a full 16 oz can of refrigerant into the system. The *rear* air conditioner seems to be blowing fairly cold now, but the front a/c is just a little cool - now that the weather is cooler (it's only about 70-73 degrees here today) I'm not sure if it is blowing cool 'cause it's cooler or if the refrigerant charge has made any difference.

But there is clear difference between what the front a/c is blowing (cool) and what the rear a/c is blowing (cold), at idle. Any ideas on what the problem could be up front? There aren't two different systems in there, are there???

 

The blend door for the front system might not be swinging all the way over to cool. If you remove the glove box, the blend door motor and linkage will be right there in front of you.