Driver's side A/C blows faintest bit of cool, while passenger's side blows normal cold. Anyone familiar with troubleshooting for this?
Thanks!

 

Having the same problem, but the more threads I read the more I'm finding that there doesn't seem to be a resolution. I'll be following this one!

 

check heater function

you may have to flush heater core with CLR

 

Mostly heater valve. Engine bay, right down,behind the radiator.
https://www.sngbarratt.com/English/#...&saveBranch=UK

 

How is this heater control water valve related to the flow of the air conditioner?
Thanks.

 

What do you recommend be checked related to the heater function?
And how would the heater function be related to the A/C?

 

By "faintest of cool," do you mean it blows just as strongly as the other side, but warmer, or do you mean there's very little airflow. Two completely different issues. That's why the heater valve was suggested. If it's not working, the driver's side is being warmed by the climate control system when it shouldn't be.

However, if you meant low airflow, then that's something else entirely. The ducts have a shut-off on them, you know, right? you can close the duct part-way or completely, which would reduce the airflow at that duct.

 

the 350 doesn’t have a DCCV....

 

The air volume is fine. Just the temp of the air is the problem.
The XR822975 cited is for an S-Type, I believe.

 

My understanding is that when the system calls for cold air, the air will be vented so that it bypasses the heater core entirely. This points more toward a blend door problem than anything else. What could the heater valve, directing or not directing water, have to do with overly hot air conditioning?

I'm having the same problem, so I'm trying to learn as much as I can, and apply logic before parts!

Thanks all!

 

This is all from memory so there might be some details that are in accurate but I believe this is pretty much how it works.The heater box under the dash contains the heater core and the air-conditioning evaporator. The hot engine coolant flows through the heater core when the heater valve in the engine compartment gets the appropriate signal.
The heater valve in the engine compartment is controlled by the climate control module under your dash. If either the heater valve solenoid or the climate control module is defective it can continuously send hot engine coolant through the heater core and the heater box. On the heater valve there is one input and two outputs. One output is for the passenger side and one is for the driver side. Air flowing through the heater box goes through both the heater core and the AC evaporator so if one side is hot and one side is cold it means that you are still getting hot engine coolant flowing when it should be shut off. This is a known fact at fault and there are lots of different posts on this exact subject

 

Not to be argumentative, but it just doesn't make sense that in order for the AC to work, it first has to chill the coolant in the heater core (if the heater was running previously and has hot coolant in it). As bafflingly complex as this and every system is in the Jag, I can't imagine that it would be set up that way on purpose. The climate control module malfunctioning part makes sense.



From the manual:
Heating/Defrosting

The heating system is an air blend controlled system. The ambient air is passed through the cabin air

filter, directed through the evaporator core, through and/or around the heater core, mixed and

distributed from the heater core and evaporator housing to the floor, panel and/or the defrost ducts

as desired. For additional information, refer to Heating and Ventilation (412-02A)

 

There is no heater valve-that was the S Type.

Put simply the heater core and A/C evaporator are both

located in the climate 'box' and by controlling about 7 flaps

the electronics produces the desired climate in the cabin.

Correct ?

 

could be true since I have an S type! Sorry I figured they were the same

 

Air is always directed through the evaporator, and some selected amount of air is also directed through the heater core, which is always hot; no valve to restrict its flow of engine coolant. How much heat gets into the cabin depends on the blend door positions. There are doors to allow air into the heater core by varying amounts, or block the heater entirely. Then there are doors to direct air out through the floor vents, dash vents, and/or defroster vents.

I had thought there was a heater valve, too, at first, but temperature is regulated by directing some amount of air, or none at all through the heater core. Each side of the front has its own blend door for that, and it appears that the OP's is either stuck, or simply unable to close fully.

I have not been under the dash for anything, so Ihave no clue what kind of job it is to access those blend doors or their actuators.

 

Okay, just got back from the garage where I was running SDD through my legit (not clone) VCM. There are two servos that the system is able to read:
Left air mix servo motor potentiometer
Left cool air bypass servo motor potentiometer

When adjusting the mode (face, feet, defrost, etc) the Left cool air bypass servo motor value changed to a discreet value (like 43% for feet, or something) and stayed there, cycling though modes showed that there was a target set and then the potentiometer would soon read the target
When adjusting the temperature, on LO and from 68 degrees up the Left air mix servo read -14% until the temp setting was within 8 or so degrees of ambient, then the Left air mix servo motor potentiometer value started to rise. Setting the desired temperature up above the ambient temp (89 I think is the max before it goes to HI) and the Left air mix servo motor potentiometer went up to 98% or so.

So, on the surface, the controls call for adjustments, and according to the car's feedback, those adjustments are happening. In other words, nothing is stuck.
What I can't tell is if these targets are legit, like is -14% actually totally closed and sealed? I won't know that unless I open the system up. I may repeat these tests with the car out in the sun, and/or with the AC actually running, as it was I was in a closed garage and using the system with the car in the "on" position (number 2).


html center image

 

I made a wrong assumption about the cause of the problem. Now that the weather is finally warmer, the problem revealed itself to be a refrigerant issue. When the weather was still cooler, I seemed to be getting cool air from the passenger's side only. But with yesterday's warmer weather, both sides just blew warm. Added refrigerant, and both sides are blowing equally cold now. It's always nice when it turns out to be something simple and inexpensive.
Thank you, everyone, for your comments, and I learned new things about the system that I didn't know before.

 

Passenger soaked up all the cold before you got it. That's just selfish!!!

 

I'm hoping that's what's going on with mine as well. I'll need to take it to a shop to have the refrigerant evacuated and refilled. I certainly don't have the stuff for it in my garage.

 

use caution with the diy kits. pure refrigerant is always better than the types laced with stop leak