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

[shorod]

Originally Posted by rquan42

Hi shorod,

This may sound dumb, but do i need a code reader to run the self diagnostic test?

As for the temperature...i don't expect it to blow out cool air consistently. When it blows out hot air...it is stuffy and way hotter than 70 degrees.

Yes...when I drop the temp to 60 degrees, it blows out freezing cold air.

While a professional scan tool that can interface with the Dual Automatic Temperature Control (DATC) module will take some of the work out of getting any climate control codes, it is not necessary. If you go back to page 1 and post #3 of this thread, you'll see some instructions on performing the self diagnostics on the DATC. There has been some discussion that if you have the heated and cooled seats the process to enable the self diagnostics is slightly different so you may need to scan through a few more posts to find the specifics.

-Rod

[rquan42]

I just finished running the self diagnostic on my a/c unit. The whole panel lit up giving me no codes. For once...I was greatly disappointed to see no codes or numbers come on the screen (outside of all of the 8's).

I know I am not entirely crazy....

[joegr]

Originally Posted by rquan42

I just finished running the self diagnostic on my a/c unit. The whole panel lit up giving me no codes. For once...I was greatly disappointed to see no codes or numbers come on the screen (outside of all of the 8's).

I know I am not entirely crazy....

It's possible (and does happen) for the DCCV to fail mechanically and not electrically. In that case, you would get no diagnostic codes. Maybe your DCCV is getting stuck. If the coolant hasn't been flushed in the last three years, that would be a good service to start with. That might fix the problem or make it happen less, but you will probably still need to replace the DCCV, if it is sticking.
There are, of course, other possibilities, but I think that the DCCV is still the most likely.

[shorod]

I'm a bit concerned by the thought that when turned to 60 degrees the A/C is ice cold. The signal to the DCCV is modulated so a slow to respond DCCV could explain the output, but it also sounds vaguely familiar with what my wife's LS was doing with a bad duct temp sensor.

-Rod

[OneMnMoose]

I have just the opposite problem. I have Drivers Side blowing cool and passengers side blowing hot. Both sides set to 90.

I've replaced the DCCV, but that didn't do it. The heater core has fluid, both supplies and return are running hot. I'm thinking that maybe it's a problem with the Drivers Air Discharge Temperature Sensor, but I can't find where it's located in my factory Workshop Manuals. A little help?

Also I see there is also one on the passenger side and the Evaporator discharge air temperature sensor. I'm guessing these are OK.

[shorod]

Seems like a reasonable place to start. From what I found on my wife's 2002, all three of the temp sensors are the same part number. I'd suggest you swap the air discharge sensors between the driver's and passenger's sides and see if the operation changes. If so, you're likely on the correct path. If no change, and you're run the self diagnostics with no codes, you may need to find someone with a professional scan tool to monitor the HVAC sensors to see if one not doing what it should. Since turning the temp setting all the way up doesn't cause full heat, you may also have a door servo that's not working.

The temp sensors are white in color and have a round base with a oval connector if I recall correctly. I think you rotate them about 1/4 turn, then you can pull them out of the duct. They are about 3 inchs long inside the duct so you'll want to pull them out pretty straight. I'd suggest you disconnect the electrical wiring before trying to remove them. Once you remove the trim panels between the dash and the firewall from both foot wells you should be able to see the sensors when looking upward.

Below is a photo showing what you'll see of the temp sensors before they're removed. I don't recall if this was the driver's or passenger side.

-Rod

[snackdaddy]

Hello all, I am new to this board but I have been following your posts. I'm having a similar problem with a 2002 navigator v8. I have searched for our dccv where the posts stated it should be, however I am yet to find it. We have no heat, but our a/c works. Any info will help I'm sure. Thanks guys....

[shorod]

Welcome to the forum!

All of the 2002 Navigators have a V8, do you know which of the 3 engines yours has (4.6L, 5.4L 2V, 5.4L 4V)? I'm not sure if they are all available in the Navigator or if it came only with the 5.4L 4V.

Also, does your Navigator have the manual HVAC controls (knobs) or the electronic controls? The service manual groups the Navigator with the Expedition so I suspect the Navigators all came with the electronic controls, but it's safer to ask.

From what I see in the Factory Service Manual, the 2002 Navigator does not have dual zone climate control. If that is the case, you will not have a DCCV. Fast Parts Network lists a heater control valve for the 2002 Navigator and it's only $35 which further causes me to suspect you do not have a DCCV on your 2002.

-Rod

[snackdaddy]

Thank you for your reply Rod. We have a 5.4 engine with the electronic controls. I also performed the test to see if there were any codes in the controller memory and I came up with triple 8s.

[joegr]

Originally Posted by snackdaddy

Thank you for your reply Rod. We have a 5.4 engine with the electronic controls. I also performed the test to see if there were any codes in the controller memory and I came up with triple 8s.

If you don't have dual controls, you should have an electrically activated temperature blend air door. A common problem with the Explorers (and probably Navigators too) is that the plastic that attaches the blend air door to the electric motor assembly breaks. This would result in no diagnostic trouble code. The part is cheap to replace, but the labor is very high because the whole dash has to be mostly removed to replace it.

[snackdaddy]

Thank you joegr. I had a feeling I would have to tear the dash apart after I didn't see that dccv, just my luck. Guess it would be wise to change my heater core while I'm in there too right? I'de hate to have to go back in there later for that. You know where that blend door is located? Not looking forward to this job.

[nuckolsk]

Ok i'm back to the same problem and need some help. I made my son drive the ls this summer since he worked around the corner and went to beach close by, so he could live with 460 ac. Had replace dual solenoid and all 3 sensor and still no fix, fiqured that it would at least throw heat at him this winter, but noooooooo. The monster is alive still , now that it is cold it only wants to run the ac. Any help ?

[shorod]

Have you run the DATC self diagnostics since replacing these items?

-Rod

[nuckolsk]

Hello rod, have not run it in a while ill give it a shot when i get off work tomorrow and let you know

[nuckolsk]

Rod - the self test showed no codes, the continuous showed codes 12 61 / 24 29 / 19 46 / 19 47 / 16 76