Rear AC not cold. I checked the blend door and it is working fine. on 2004 Mercury Monterey

The AC system had a leak which I had fixed. The front AC works fine. When I took the side panel off I checked the blend door. It moves full travel from cold to hot. I started the van and the AC pipes going in were the same temperature. The small line looks like it goes into a temperature controlled valve. Not sure how that is suppose to work. is there a secondary compressor for the back AC? Maybe electric?

Asked by for the 2004 Mercury Monterey