Another A/C issue...

[CharleySuede]

2001 Lincoln LS 3.9L V8

I hate to post about this after reading many related threads, but after 20+ hours of research I have not found what I am looking for.

Issue: blowing a blend of warm/hot air with cool air on driver’s side. Passenger side blowing straight warm/hot air.

Blows cold at startup then blends after a 5 minute drive at 30mph. Blows more hot at higher speeds.

Sometimes it is cooler at 60 degrees, sometimes it’s cooler at 65 degrees.

All vents blow as they should, with the exception of the temperature.


Replaced DCCV last year (not sure who made it)

Professionally replaced A/C compresser (OEM) last month

DATC diagnostic test only shows code 1242

I will not be surprised if the DCCV needs replaced again, but I would like to know the troubleshooting steps to determine if the issue lies within
1) DCCV
2) recirculation door (code 1242)
3) faulty DATC/EATC

Thank you in advance; I know it must be tiring to tell people that their DCCV needs replaced.

 

[joegr]

It certainly sounds like a mechanical problem with the DCCV. Mechanical issues won't show up on the diagnostic.
Pinch off the passenger side heater hose, and it will stay cool all the time. The middle pin of the DCCV should have battery voltage, and the outer pins should each be at ground (temperature set at 65). If those voltages are correct and the passenger side is heating, then it's the DCCV.

If the valve is at all gunked up, then you need to flush and replace the coolant.

 

[CharleySuede]

I am pleased to have your attention, joegr. Your reputation for knowledge of these finicky cars is welcome.

Would you be so kind as to describe which of the 5 hoses I am to pinch off?

 

[joegr]

Top left from the DCCV, I think.
Really, there's not much need to do this. We know that water is flowing in the passenger core, just need to know why. If you do the voltage tests and the coils have power, then it's the DCCV.