AC temp difference between vents

Hi all,

I'm hoping for some help here. A while ago I noticed my air was a little warmer, especially the passenger air vent, so I checked refrigerant pressure and it was low, recharged the system and all was good for a few days.

The symptoms came back every couple days, so I took it to a shop to have it checked and repaired. A new evaporator and expansion valve later I go to pick up the truck. The driver side blew cold, but I noticed the far passenger vent was a little warmer. The mechanic checks the pressures and it's exactly where he charged it to. This was Friday night so they told me to bring it home and decide if I think it needs to go back for a second look (free of charge).

As of tonight my center left vent is blowing around 47, but the far right is only going down to about 62. Has anyone seen this much difference between vents with normal pressure? I'm wondering if there's an issue or if this is normal by design and I'm just over thinking it now...

I understand the far passenger vent blows warm first when refrigerant is low - that's how I found the original issue, but I'm wondering if it blows a little warmer all the time, even at normal pressure?

Thanks in advance for any input or if one of y'all want to go check for comparison!

 

@PennSilverTaco Didn't you fight this situation?

 

Low on refrigerant.

 

https://www.tacomaworld.com/threads/evap-core-replacement-almost-10-months-later.616830/

 

Thanks for the replies!

@JGO that was the original issue, but it seems to be holding pressure now.

@tomwil thanks for that. That is exactly my story as well!

I am very curious if there is usually a slight temp difference between the far right vent and the others, and no one really pays it attention until they have issues.

 

I think it's natural to some degree. The air box is in the center, so those center vents get the most flow and seem to be the coldest. The outer vents will always flow a little less, and they always seem to run a little warmer. I think the air going to those outer vents warms up a little running through the (hot) dash.

 

Yeah I was thinking that vent does have a longer duct run so I would expect it to be slightly warmer - I just have no idea how much is normal.

I'm almost battling the crispy connector so my blower doesn't want to work except on high. That's another saga...

 

Maybe this will help:

I just replaced all three servos on the airbox over the weekend, so I am certain that all air flow is going where it's supposed to go, and the temp of the air is where it's supposed to be. That said, my outer vents blow a little warmer and with less air than the center vents. No doubt about that. And I put my manifold/gauge set on the A/C system and my pressure readings are spot on for the outside temps. I really think it's operating as intended.

PS - the blower motor connector is a 10 minute fix. Don't sweat it.

 

Thanks @Fullboogie I think I'm going to leave it as is.

Unfortunately I've replaced the AC connector before. I read some threads just now and might try some solder on the contact to keep the connection tight. I hate to keep replacing the same parts...

 

Did you replace the resistor and the connector at the same time?

 

@Muddinfun yes I did. That was a couple years ago. It's very intermittent now whether it works or not. Sometimes a shake of the harness at a red light will keep it working for weeks, then it goes through phases like now where it stops working 30 seconds after I mess with it. Connector looks like all the others - one burnt pin.

 

If I remember correctly the two outer most vents are fresh air vents so they always pull some air from outside so there may be a small temp difference but it should not be 10-20 degrees.