Dual climate control blowing heat on AC (DCCV removal instructions in post #107)

[Smoke2071]

Having read this entire post, I have to say there is some very good info here, unfortunatly it has not fixed my problem.

I have this same issue with the wifes 05 LS, heat on pass side cool air on driver side. B1265 code as well as 1262,1242,2798.
Changed DCCV cleared codes with Snap-On Modis topped off coolant.
The problem persists as does the 1265 code, I have ran the self diagnostic several times and also scanned it with the Modis and still get the same 1265 code.
I have noticed that the heater hose on the left side of the DCCV gets very hot while the one on the left does not.
The DCCV has been replaced with a NEW unit, so do I have an elecr=trical problem or is it a bad new DCCV ?

[joegr]

Originally Posted by Smoke2071

Having read this entire post, I have to say there is some very good info here, unfortunatly it has not fixed my problem.

I have this same issue with the wifes 05 LS, heat on pass side cool air on driver side. B1265 code as well as 1262,1242,2798.
Changed DCCV cleared codes with Snap-On Modis topped off coolant.
The problem persists as does the 1265 code, I have ran the self diagnostic several times and also scanned it with the Modis and still get the same 1265 code.
I have noticed that the heater hose on the left side of the DCCV gets very hot while the one on the left does not.
The DCCV has been replaced with a NEW unit, so do I have an elecr=trical problem or is it a bad new DCCV ?

Ignore the 1265 code, it is a false failure - Your LS does not have a cold air bypass valve.
" B1265 1265 Cold Air Bypass Door Actuator Circuit Failure Invalid code. Vehicle not equipped with cold air bypass door actuator. Ignore this code and continue diagnostics. "
http://deneau.info/ls/s6x~us~en~file...tm~gen~ref.htm

Is it heating on the passenger side when it should be cooling, or is is cooling on the driver's side when it should be heating?

If cooling when it should be heating, then unplug the DCCV electrical connector. You should then get full heat on both sides. If you don't then the valve is bad or you have a coolant clog somewhere on that side. If both sides heat now, then you have an electrical problem with the wiring to the DCCV or with the DATC.

[shorod]

Welcome to the forum!

It sounds like you may have a combination of issues, but the majority of your codes indicate separate actuator failures. That seems like it might be more a problem with the control head (DATC) or one of the feeds to the DATC that is common between the actuators.

To check the function of the new DCCV you should consider checking the voltages to the solenoids to find out if the DCCV is doing what it's being commanded to do (open one solenoid and not the other).

-Rod

[Smoke2071]

Thanks, guys,
After further reading, ShopKey5 (snapon) confirms 1265 code is invalid for any LS built after 12/31/2002.
So, ignoring 1265, I have no other codes present at this time, yet I still have heat on the Pass side when it should be cold.
Driver side working properly.
As I have replaced the DCCV with a new unit and I still have the same issue, would the next step be replacing the DATC ?
I have checked the wiring schematic and the wiring appears simple enough, going from the DATC to a relay and then to the DCCV.

I failed to mention in my first post,
The "service parking brake" warning came on at the same time this issue started, after talking with Lincoln service manager, (and finding out that I was out from under warrenty by 12 days) he said that it was more than likely the DCCV as it will set the parking brake fault code when it goes out. That is what led me to replacing the DCCV (89.99 from AutoZone/ 400.00est. from Ford)

I hate to be a " replace parts til its fixed" type of mechanic, but that seems to be the next step here.

[shorod]

I'd check for voltage to the two solenoids of the DCCV before shotgunning the DATC. If I remember correctly, battery voltage closes the valves, therefore if you were to unplug the DCCV and it's the problem you should get full heat on both sides of the instrument cluster. Of course that's assuming you don't have a stuck valve in the new DCCV.

-Rod

[Smoke2071]

Rod,
I unplugged the DCCV last night and got heat from BOTH sides.

The "new" valve does the same as the "old" valve in that it is heat ONLY on the pass. side and normal operation on the driver side.

So does that sound like a bad"new" valve or electrical, either wiring or DATC.
I'm at a lose here, Wiring appears to be ok, the car has never been in a collision, never had any repairs other than a brake booster several years back.
It seems odd that it would be a wire that has been rubbed, cut, or pulled out.
If I have to take the dash apart to check the DATC, I would prefer to have one in hand to replace it with if that is the problem.

I guess I'm looking for an educated guess here.

[shorod]

Since you got good heat from both sides with the DCCV unplugged, that suggests the problem is not the DCCV. You could release the wire from the connection at the DATC that signals the DCCV and see if the DATC is intentionally providing voltage to the valves. You'll need to release the wire from the DATC though just in case the wire is shorted to power somewhere between the DATC and the DCCV.

I don't recall ever reading of someone whose issue was due to a faulty DATC, therefore I'd be more suspect of one of the inputs to the DATC. Does the Snap-On scan tool allow access to the DATC datastream? This is how I ultimately found the bad temp sensor on my wife's LS. My OTC Genisys scan tool showed an unrealistic temperature for one of the temp sensors in the cabin. I swapped a couple of the sensor around and the symptom changed as well as the unrealistic value following the sensor. Replaced the $21 sensor and all was well again. If the Snap-On does not offer datastream for the DATC you could try moving temp sensors around (same part number) and see if you get the symptoms to change.

-Rod

[joegr]

The DATC sends full power to each valve to turn it off (as in no heat). It sounds like either the new DCCV is defective (unlikely) or power is not getting to the passenger's side of the valve. I would measure voltage at the valve connector while the valve is plugged in to see if it is being powered on that side.

There is no need to guess at the problem. The troubleshooting steps for this problem are in the document I linked in before.
http://deneau.info/ls/s6x~us~en~file...tm~gen~ref.htm

Go to pinpoint test J and go from there. It is not at all hard to pull the DATC out to check the wiring. I'd do that before ordering a new one.
Here's the service manual if you need to look up how to pull the trim to get to the DATC.
http://deneau.info/ls/

[joegr]

Originally Posted by shorod

... You could release the wire from the connection at the DATC that signals the DCCV and see if the DATC is intentionally providing voltage to the valves. ...
-Rod

Rod - Just to make this clear.

Power to valve = valve closed and no heat.

No power to valve = valve opened and full heat.

You want the DATC to be providing "voltage" to the valves.

[shorod]

Correct, my post was relating to checking for a short to battery power between the DATC and the DCCV, in case there was a wiring issue somewhere that was causing the wire to the DCCV to be pulled high and causing the lack of heat to one side. At the time of my comment we already established that with the DCCV unplugged there was heat on both sides. That means that the DCCV is not stuck and for some reason one of the valves is receiving voltage to open. Is the voltage from the DATC or due to a short to battery in the wiring? That's what that comment was testing for.

CORRECTION: Now that I reread post #140 above I see that the concern is full heat on one side and "normal" operation on the other. I'm used to this time of year reading about people not having heat to one side or the other versus having too much heat to one side as is suggested in #140. So we are not looking for a short to battery but possibly an open circuit. So much of the concept still holds, but instead he would want to verify continuity between the DATC and the DCCV and not to ground, then confirm that the DATC is NOT providing battery voltage at the connector. I suspect that is similar to what is described in the link to the service manual, but the manual should identify which pins to focus on for the passenger side.

-Rod

[Smoke2071]

Ok guys, this issue still has not been resolved, partially because I haven't had time to deal with it, and partially because she won't slow down long enough for me to look at it when I do have time. LOL

Back to the problem.

I have been able to get a graph on my MODIS of both the driver and passenger water valve counts.
The driver side will move up and down as needed when the temp. is changed on the control panel.
The passenger side is flat lined (no counts) unless I up th e temp. to 90, then it will show counts at the upper limit only.
I assume that the counts will be the valve opening and closing to regulat temp as needed.
So with that in mind, would this suggest a temp sensor on the passenger sid being bad ?
if so, where is it located ?
I understand that both the pass. and driver sid temp sensor is the same part # so I should be able to swap them to confirm. Again, where is the location of each ?

Thanks again for the assistance,

Jimmy

[shorod]

I should have taken more photos when I worked on the wife's car. I seem to recall on her car that there was one in the center of the dash on the passenger side and three on the driver's side. I think the middle one on the driver's side is the one that I swapped with the one on the passenger side. I had to remove the passenger side under dash trip panel which allowed me to access the wire connector and sensor. Same for the driver's side. There was a trick to getting the sensors out, but I don't recall if it was a quarter turn or what it took besides patience and trial and error.

-Rod

[Smoke2071]

Thanks Rod,
I located the temp. sensors, and swapped the d & P side, no effect on the system, still have heat on the pass. and working properly on the driver side.
I also was able to graph the DCCV and found, contrary to my last post, that both valves had "counts".
I also noticed that the DCCV made a "pop' or "click" type noise as it worked. I assume that the valves were opening and closing at this point, but still no effect on the problem.

I have not checked voltage to the DCCV or the DATC, as the graph shows that DATC is sending the command to the DCCV.

So, what's next ?
Bad "new" DCCV, or bad DATC ?
:runar ound:
I feel like I'm chasing my [tail] !

[shorod]

You could try jumpering the passenger side DCCV to battery voltage to force it closed and see if the passenger side is still full heat. That would tell you if it's likely a DCCV issue. I suspect not and that the DCCV is doing what the DATC is instructing it to do. You could also backprobe the signal to the DCCV to confirm that it's doing what it's instructed to do. But that wouldn't necessarily mean the DATC is bad, it could still be an input to the DCCV. You'll want to monitor what the sensors are reading, what the position information from the servos is, and see if it all makes sense. Did you graph the temp sensor information before and after swapping them to see if both are giving expected numbers? You were questioning the values at one point, don't completely discredit your first impression....

-Rod

[Smoke2071]

Rod, I checked the graph before and after the swap, got the same reading on pass side as before.
I'm leaning toward the DATC.
If my memory is correct(doubtful) the DATC was replace right after this car was purchased in 2006 for this very problem.