2008 Ford F150 - 5.4L A/C Not Engaging FIXED

[bakerauto]

2008 F-150 5.4 liter

Installed New Instrument Cluster, Programmed it. All Was Fine. Came back with A/C inop. New PCM and Heater Control Head were Installed.......Still A/C will no engage.

Any suggestions please.... Thanks

[steven kiser]

Was it working before? Who did the programming? Is the compressor clutch fuse blown? Will the clutch engage through your scanner? Is this a climate control system? The more information supplied the better. I would start with the fuse and then to scanner command. If it commands on and the clutch doesn't I would go to the relay and see if it's clicking and if it is look for a broken wire. If not swap out with another relay and if still no look to the command wire from the module, if yes look for a broken wire, if no look to the input side for the switch command as well as the pressure sensor input. They have to be within specs to allow module to command on. If all tests out you have a bad module. If it's a climate control system you need to look at all the sensor readings especially the internal cab temp through a scanner. Now I'm not sure but I think there are two or three fuses that have to do with the a/c system. I've had a fair share of bad clutches in Fords, especially the ones on the right lower side where road dust, rain, salt seem to get in.

[bakerauto]

Checked All fuses. Cannot get Instrument Cluster To Communicate with PCM. Not Sure if A/C was working before...only got truck to install New Cluster, was during winter months.

[ricmorin]

Does this have Automatic AC?

[ricmorin]

I'll assume that it does.

The IPC is connected to the HVAC in two ways. First, the heated window input and second, the UBP line. If you cannot communicate to the IPC, then it may be compromised in some way. That may affect HVAC module operation. I'd simply disconnect the IPC from the network, then see if AC returns. If it does, then there is a problem with the IPC. You can also monitor voltage on that line. Sometimes a bad module will pull the voltage down or hold it high and prevent communication.

Give that a shot and report back.

[ricmorin]

Oh, I almost forgot. I'm sure you've been in the PCM already, but misfire codes will inhibit AC operation until they're cleared.

[bakerauto]

Had to Force As Built Data into Instrument Cluster, and then enter Security Code. All Is Good Now. Thanks All For the Help and Suggestions.