Factory Chassis A/C not working

[windrider]

If the PCM controls the ground to the AC clutch relay, then your diagram in post #7 is useless, as it shows a hard ground to the clutch relay. I'm not trying to argue with success, glad they found something. I just don't see the PCM anywhere in the wiring diagram. Just making a note for those in the future, this wring diagram is missing something.

[NWJeeper]

Well, way to make things even more complicated Ford! Why in the world do they need the computer to control the ground. In most A/C applications the ground is just that, a ground! The 12 volt power to the clutch is switched on and off as needed for the sytem to work.

Give me simple and stop controlling everything with the stinking computer!

[blightle]

Windrider - keep in mind that the wiring diagram is just for the 3rd party A/C system. In the note in the upper right of the diagram it basically says that the "dashed" lines are illustrative of parts that may be found on the chassis side of the vehicle. Ford did say that the diagram was only somewhat helpful in that the colors of the wires were apparently different.

I too have no idea why a PCM would need to control the ground to a relay for the A/C unless there is something in the engine programming where in certain situations if there is a significant loss of engine power the PCM will shut down all but the most essential components to keep the engine running so that you can at least limp home.

[windrider]

Being "new", probably "CAN" and not OBD II, the PCM will control essential functions, even switch to 4 or 5 cylinders in case of overheat, and shut the AC off. It will also shut the AC under full acceleration. They have been doing this a few years. They usually do this with the AC control feeding the PCM, and the PCM feeding the clutch relay. Regardless, the clutch "ground" in the diagram must be wired back to the pcm, and is not a hard ground. I'm not trying to confuse, just help those that do their own work, and may reference this post in the future.

[TulsaSteve]

Originally Posted by NWJeeper

Give me simple and stop controlling everything with the stinking computer!

This gave me a good laugh. I went down a 4.5% grade a few days ago and barely touched the brakes. The computer was working the transmission / engine like a dream and I just walked right down the hill while others were struggling.

Computers.. Can't live with em'... Can't turn em' off because we can't remember what happens if we do...

[ArkyGeorgetown330TS]

Well I am about to take my 330TS in for a few items to be fixed after our 2nd trip out. One is the dash air is not working. I have printed off the schematics posted above to take with me and hope it will help. The thing that gets me is we forgot to check the dash air when we did our PDI. I can only guess is because it was cold when we took delivery and did not even think to check it. Yes it was on the PDI and I just had a brain F__T and did not check it off. Oh well its like they always say.

[cfsoistman]

Originally Posted by ArkyGeorgetown330TS

Well I am about to take my 330TS in for a few items to be fixed after our 2nd trip out. One is the dash air is not working. I have printed off the schematics posted above to take with me and hope it will help. The thing that gets me is we forgot to check the dash air when we did our PDI. I can only guess is because it was cold when we took delivery and did not even think to check it. Yes it was on the PDI and I just had a brain F__T and did not check it off. Oh well its like they always say.

Gotta be careful with those Brain F_ _ Ts, that where S_ _ tty ideas come from!

Good luck with the AC! Hopefully it will be something simple.

[mbtelguy]

The following site provides complete manuals/troubleshooting guides for Evans Tempcon including the FR provided schematic ( with explanation ) posted earlier. Good information to have.


Evans Tempcon, Inc

[blightle]

So I started this thread about a month ago and finally have a resolution on why my factory A/C would not work in my 2011 Georgetown. Ford spent almost 3 weeks working on my Georgetown. Numerous calls to Engineering in Detroit, calls to techs at Forest River about the wiring of the Evans Tempcon 3rd party A/C system, etc. Nothing was showing up as a problem. At one point Ford thought it was a bad PCM but after ordering a new one, later determined that the PCM was not the issue. Finally on Monday, they were running tests again and the PCM threw an error code for the first time. Turns out that the low pressure switch was bad. Never showed up in all the times they had run the test before but it must have deteriorated to the point that it would send a trouble code or something. Must have been a new pressure switch design for 2011 because they had to have the switch overnighted from Detroit. Got it this morning, installed it and now the A/C is ice cold - finally. Just in time for Memorial Day Weekend and our first real outing with the RV.