Do you have the T2 box plugged into the 4 pin plug or the 9 pin serial port on the harness??

What harness do you have? the "all port" cable or just a basic Ez steer cable?

Check it out here. 

http://trl.trimble.com/docushare/dsweb/Get/Document-415276/EZ-Guide250_1A_CablingGuide_ENG.pdf

Just checking the basics here, must be your first 250?    If the dealer had old inventory, the T2 could still be on the Ez Guide Plus firmware also.