AC blows HOT intermittently - 05 LS V6 Appearance Package

[sgkmm]

2005 Lincoln LS V6 Appearance package

My AC works fine for the first 15 minutes of driving. Then both sides begin to get hot. I can press the defrost and OFF switches followed by the AUTO switch to enter the diagnostic mode. I get a 1265 code (Lincoln Maintenance Manuals tells me to ignore this code for my car). If I leave it in this state of flashing 1265, most of the time the system returns back to cold again. Once it is back to cold, I can exit the diagnostic mode and press the AUTO button to turn it back on.

I have changed the DCCV with an OEM part, no change.

I have bled the engine coolant system.

Any ideas?

 

[joegr]

What happens if you put the climate control on 60?
Was the replacement DCCV a new part?
Have you double checked that the connector was clean and is now fully seated?

 

[RigsLS]

CHECK CORRECT COOLANT CONTROL VALVE OPERATION

- Remove the passenger side cowl cover.

- Clamp off the 3 heater hoses going to the heater core, as close to the heater core as possible.



- Key in ON position.

- With the engine running, set the DATC module to 16°C (60°F).

- Is cooling restored?



Other possibilities,
- A/C clutch relay
- A/C compressor clutch/field coil
- DATC module
- Evaporator discharge air temperature sensor
- Ambient temperature sensor
- PCM



* A/C system pressure

CHECK THE REFRIGERANT SYSTEM PRESSURE

- Key in OFF position.

- Connect the manifold set to the service ports. Refer to Manifold Gauge Set Connection.

- Is the pressure between 345 kPa (50 psi) and 1,724 kPa (250 psi)?




* Refrigerant System Tests

 

[sgkmm]

Putting in 60 is not as effective as entering the diagnostic mode.
The DCCV was a new part. Is it possible to get a bad part or it failed shortly after installation?
The connecter on the DCCV is clean and has positive connection.

 

[RigsLS]

Does the A/C compressor attempt to run during your intermittent hot flashes?
Are there any "gargling" noises from behind the dash when A/C demand is requested?

 

[RigsLS]

... The DCCV was a new part. Is it possible to get a bad part or it failed shortly after installation? ...

If you would have clamped off the 3 heater hoses going to the heater core and A/C cooling returned, you'd have the answer you seek.


~ I'm leaning towards, you have a leak somewhere and you are now low on system pressure. It will shortly stop working altogether.

 

[LS4me]

Does the A/C compressor attempt to run during your intermittent hot flashes?
Are there any "gargling" noises from behind the dash when AC demand is requested?

Are there any traces of green dye under the compressor area??

 

[joegr]

...My AC works fine for the first 15 minutes of driving. Then both sides begin to get hot. ...

This is a classic symptom of the DCCV opening for some reason (could be the DATC, wiring, temperature sensors, or the DCCV itself).

I am making the assumption that by hot you mean heated air, not just uncooled air that is a little above the outside temperature. If this assumption is true, then you can ignore the refrigerant system as a cause for now. On the other hand, if the air isn't heated, then it could be a low refrigerant level problem.

 

[sgkmm]

I installed two wires on back side the DCCV connector to measure the voltage when the system is operating correctly and when it is not. The center pin has a constant 12 VDC with the ignition off. The DATC defaults to provide 12VDC to each side which allows the DCCV to stay open (the heat is on). When the DATC provides a ground, the particular side valve closes and the AC will cool that side. I measured .25VDC on both sides when the system was working properly. I ran the engine until the heat started and checked the voltage on both wires separately; they both read .25VDC. This told me that the DATC was not changing so the DCCV was unable to stay closed. I changed the part yesterday and have had no issues so far. I will keep you posted.

HERE IS HOW: I took two wires 20AWG (8" long) and stripped the insulation back 1/2" on both sides. Then I tinned them to stiffen them. Used a little saliva and pushed them in the rear of the connector. I ohmed out the wires to the pins to ensure I had positive contact. Then I reconnected the harness to the DCCV. Once the test was finished, I simply pulled the wires out.

 

[sgkmm]

So Far, The second BRAND NEW DCCV seems to have fixed the issue. I will post again if the problem returns.

 

[sgkmm]

Well, the other day, a very hot day (98 deg F), my AC started to blow hot air again. I was doing a lot of running around so there were a lot of starts and stops with the ignition. I tapped on the DCCV and the AC would blow cold again. I was hesitant to shut the car off if the AC was running cool. Is this a DCCV or air in the coolant problem?

I thought i read once that the DCCV had a bad batch go out... could I have gotten one?

 

[joegr]

Air in the coolant could cause a no-heat problem, not a too much heat issue.
Your new DCCV could be failing (maybe you should've have bought OEM, if you went aftermarket), or it could be that you don't have the connector completely engaged or have a bad connector.