Do you have the dual climate control (i.e. individual temp dials for drivers / passenger side) ? If you do, adjusting the temp dial on the passenger side should be the one changing the blend door directing hot/cold airflow mix to the passenger vents. Find which motor is being operated by moving that temp dial and that would be the one I would focus on. I don't really have a good knowledge of how the hvac venting works on the HL so am just throwing out a possible path for you to pursue.

 

Thank you. This is the base model and does not have a pass/driver setting. From what I have read (depends on who is doing the talking) the term dual zone is thrown around a lot. I have seen where, like in my other cars, you can adjust the drivers/passenger temps separately. I have also seen where the term refers to the rear ac/ heat as dual zone... Which really muddies the water for me.
I can see 3 actuators on the passenger side and some docs say the 3rd is on the driver side model dependant. I'm really curious which one moves heat from side to side...

 

If you do not have separate temp dials for your trim, then I doubt you can adjust the temp settings for driver / passenger side. I am more to thinking you may have some heater core blockage going on where the air flow is pulling warmer air to drivers side at passenger side expense?

I agree that in your case of the base model, the dual zone would indicate front and rear sections of the car.

It would be helpful to post a photo of your HVAC panel with what controls you actually have (along with any steering wheel controls for same).

 

As per request, here are 2 pictures. The control panel and the other showing the 3 black solenoids, each stacked on top of each other {All ducting is white so they stand out nicely}. From what i can tell the top one is just for the recirc. The bottom most one moves when i change the level of airflow {Feet to head, mixed, etc}. The middle one changes when i move the hot to cold....the issue i have is that my drivers side blows very hot from the top, feet and rear seat while the passengers side is much colder in all 3 places. I'm stumped....which diverts air from side to side? TIA

 

Those are not solenoids. They are servos / motors.

Pretty sure there is no side to side motor/damper. Think as the front as two systems where both should be operating in tandem/sync and driver side is working correctly and the passenger is not, my guess is a stuck closed air mix control damper.

I don't envy anyone tackling that. Everything comes out.

 

Dang ... That would make sense. I've searched everywhere and I can't find a diagram where one of those things would be up in the dash.

 

I would think the ducting would simply be a "Y" where the blended air would simply flow to both drivers and passengers side equally. The "stuck closed air mix damper" should therefore affect the temps on both sides. You really need to find a repair manual that shows the ducting / servo motor locations to help in understanding the possible problem.

You say the driver side air temps are 140 on both vent / floor outlets. What are the temps on the passenger sides compared to this reference point?

As a further test to isolate issues, what are the cold air temps coming out both sides when AC is cranked to max cold? I know that when refrigerant gets a little low, the passenger side discharge temps are much warmer than driver side due to the evaporator not having uniform cold temps across the entire unit. I am wondering if you have a partially blocked heater core that is limiting the hot water to flow thru on the side that vents to the passenger side in a similar scenario.

 

My interpretation is based on a service guide, not 1st hand knowledge.

While I agree your assumption makes sense and would be mine had I not looked at a service manual diagram. This is the diagram for a manual HVAC (not Auto, independent driver/passenger control). According to the diagram, while there is one Air Inlet Control Damper ( fresh / recirculation) at the blower, there are 2 downstream independent driver/passenger Air Mix Control Dampers apparently. If that is accurate my guess is that is a cost-saving measure to share HVAC design/parts across both HVAC types (auto/manual) where possible. I circled where I guessed could be a problem. I should clarify, instead of saying 'closed' as that's a matter of perspective, damper may be in a position that bypasses the heater core on passenger side.

I'm having a very hard time visualizing a partially blocked heater core affecting one side but again I haven't been in there myself.

Now if OP is not getting passenger air flow, ignoring temperature, that's another issue.

Anyway you look at it, I'm confident any cause of this anomaly would likely be an enormous undertaking to address and OP ought to consider if he is up for that (depending on age/condition of vehicle) before going any farther or living with it. Very few HVAC fixes don't require removing the entire dash, I mean everything, and in many cases removing refrigerant as well, etc. It's very unfortunate and dread that possibility for myself.

 

My interpretation is based on a service guide, not 1st hand knowledge.

While I agree your assumption makes sense and would be mine had I not looked at a service manual diagram. This is the diagram for a manual HVAC (not Auto, independent driver/passenger control). According to the diagram, while there is one Air Inlet Control Damper ( fresh / recirculation) at the blower, there are 2 downstream independent driver/passenger Air Mix Control Dampers apparently. If that is accurate my guess is that is a cost-saving measure to share HVAC design/parts across both HVAC types (auto/manual) where possible. I circled where I guessed could be a problem. I should clarify, instead of saying 'closed' as that's a matter of perspective, damper may be in a position that bypasses the heater core on passenger side.

That is interesting observation and is plausible. The servos / vent plumbing would be identical between Single Zone / Dual Zone trim levels where the Dual Zone trim levels would have the Sync button, Driver / Passenger separate temp dials controlling the servo's. In OP's case of Single Zone trim level, the Sync button input to the HVAC module would in essence be "on" all the time and there would only be a single temp input.

So the task is to find which servo controls this function and replace it. If that does not cure the problem, then a more likely case is that the damper / vane deflector setup within the duct work has become stuck and no longer moves as it should. Repair of this would be to remove the whole dash and vent pieces to repair / replace the defective area. I would not even consider doing this and just live with the slightly lower exhaust temp from the passenger vent.

 

If you haven't already...if it were me, I'd take a closer look at the double servo ('lower/middle') part 87106-0E140 in your photo and with the car not running (less noise) adjust the temperature dial slowly back and forth and listen closely for odd clicks/sounds. Keep in mind while the servos motor/gears may be engaging, downstream control mechanisms (gears/arms/hidden damper(s),etc) may not be engaging and moving as they should.

This thread caught my interest because one of servos started acted up the other day on me. I heard the faintest clicking at idle and quickly narrowed in on that double servo (middle bottom in your photo) by doing what I suggest above. It randomly just started stuttering. Fortunately it was resolved from some combination of restarting vehicle, unplugging/plugging servo connector, moving temperature (air mix) dial through range. 🤞

 

For the OP, i did some temp measurements on my 2012 HL Ltd the other day. I do have the dual climate control for front where I have separate temp dials for Drivers / Passenger side. Temps were set to max hot on both sides. Engine coolant was shown to cycle between 180-185 F on my OBD2 live data feed. I used a non contact infrared thermometer and shot the laser pointer into the vent on all angles to read the hottest spots. The mode switch was set to vent only and fan speed was on max setting / recirc was ON. Left vent, both center vents readings were very similar ranging between 152 and 158 F. The far right passenger side vent was always a little lower, reading between 146 to 152.