I don't think it matters. Whether the blend door seals well or not, the chamber housing the heater core is still 210 degrees and the heat has to bleed over to the cooling side. Yes this sucks, but in Tucson this week it was 105 and I blew 41 degrees with the shut off valve. Trust me, if there was a perfect truck I would buy it. I've had them all and this is by far the easiest fix to live with....
I clamped my hose off last summer and recently clamped it off for this summer, as it‘s starting to get hot in Central Texas. I usually run the fan on the 2 - 4 setting with the temp set all the way to lo and the recirculate turned on. I adjust everything with the fan settings and don’t use the auto temp thing.
I keep an old school HVAC thermometer stuck in the front, driver’s side vent so I can occasionally monitor the air temp. Running the fan on 2 - 4 with outside temps in the low to mid 90s, it’ll get down to 48 - 49 degrees which is tolerable.
The other day, it was pretty hot and I cranked the fan up to 7 and just let her blow for 15 to 20 minutes. When I got home, I checked the thermometer and it was at about 43 - 44 degrees. That’s pretty good and clamping the hose or installing a valve like a lot of folks are doing is a simple fix if your AC is one that’s performing poorly.
Other than this issue, I love my truck and I have no intention of bringing it to the dealership to experience frustration and disappointment on an issue that FCA is not even acknowledging.