The A/C in my 2005 has never been great, but it's been tolerable. In really hot weather, the only way it cools is on RECIRC (compared to my Subaru, which is the opposite, and will still freeze you out of the car even when it's 110 out).

Anyway... here in San Jose, my truck's A/C works pretty well. There is a slight temp difference between the driver's vents and the passenger vents, but it's no more than a few degrees. BTW, my truck does NOT have the dual-zone climate control.

BUT, this past weekend, I went over the hill to Reno. Up there, and going over the pass, the passenger side vents basically didn't produce any cold air at all. The driver's side were a nice, cold 38 deg. The pass side read 53 deg on my little infra-red temp probe. Every now and then, they'd cool off (barely) for a couple seconds, but most of the time, they were not cold. This was the case regardless of whether I was using Fresh or Recirc mode.

Why, since I don't have dual-zone climate control, is this happening? And what could be causing it? The problem is not that bad here at sea level, but going over Donner Summit (7200') and in Reno (4500'), it's terrible.

Rob

 

You are low on freon. Most common issue.

 

I could understand all the vents being warmer than usual due to low freon, but not half and half like I described.

Rob

 

x2 on low freon. I had the exact same issue last year and low freon was the problem.

 

I've heard (but not seen for myself) it has to do with the way the evaporator coil is positioned. On other cars it stands up right... on this Dodge it lays flat and the input/output of the evaporator are at opposite ends. There is a divider in the middle that diverts half the air over to the driver side and the other half to the passenger side. Problem is passenger side is on the half of the evaporator that has the output... so the refrigerant is already warmed up some because it just traveled through the driver's side of the evaporator.

X3 Low refrigerant.

 

Okay... I have an R134A recharge kit; I'll dig it out and try to add some.

Thanks!

Rob