Tradewinds VDC location

[bigdog]

I need to find out where the VDC is located on my '01 LTC as I'm having low air warnings on the rear airbrake system.Freightliner says that this is what the problem is,but that they don't install it,just send it along with the chasis and National put it where they wanted to..I have the info on repairing the VDC problem from Gary over at the Freightliner forum,but need to know where it is.

[Submustang]

Ours is in the right rear basement compartment with the inverter and slide controller boards.

[Airtool]

Attached is a picture of what I know as a VDU unit that monitors the air pressure in the Primary and Secondary air supplies.
Red is the rear system and Greed is the front system. It might help.
This unit was mounted under the Dog house on the curb side on some of the 2000 to 03 units.

Dick