I did disconnected battery, did it again just for kicks, connected positive to negative for one minute, then left disconnected overnight. No luck

 

That's interesting.

What's not known is if the AS Module is communicating with the BCM or not, try disconnecting either ride-height sensor, this should generate a "Service Air Suspension" message and a DTC.

If this is not the case then basically either the

• AS Module comms lines are disconnected.
• AS Module is not powered
• AS Module is faulty.

A powered and connected module should report back it's status.

 

I unplugged the 16 pin, no error code. Only change was the light on the dash button went from always on to always off.

This is with compressor connected the light remains on regardless, same with the switch in the hatch, it is the reverse when unplugged, always off.

 

"light on the dash button went from always on to always off"

This is significant because the lamp is directly controlled by the AS-Module, of course unplugging the 16-Way disconnects it, significantly being constantly being driven by the module suggests a faulty module:-

• Lamp always ON
• No communications, no warning messages or MIL (engine warning)

However before replacing the module check the Ground Tag G402 on the AS-Frame and make sure both connect to chassis - essential !

 

I tried to drop the entire compressor, these lines would not budge, they are the lines to the air bags

I assume this is the faulty control module? Aftermarket air suspension complete kits sell for about the same, if I could figure outbid plugging in a new module would fix I’d do it, but spending complete replacement money only to find ot doesn’t work is a bit risky

 

You can not disconnect the quick fittings if the system is pressurized. You have to deflate the system before you can “budge” the fittings. There is the quandry. You need a Tech II to do that. Or you have to wait till system does that by itself via a leak. These are regular QD fittings. Push down on outer ring while pulling tube out.

 

Closing the loop, it was a body wiring harness problem as suspected by oceanbrave. It actually wasn't as big of a nightmare as I thought, but still a pain.

 

@ChrisP
Well done so pleased you've got it working and thanks for "closing the loop" for future reference, any other details you could add would help too👍