Ok these xm series trucks generally came with the GE EV100 lx or zx controls so based on the the code13 is not a valid error code so this number may be an hour meter or battery charge level. But if this machine has a separate HM gauge and/or BDI indicator then I'm not sure what that is.
And even by chance this truck got an SEM SX controller the error codes still apply the same.
As for the code7 that is an accelerator input error.
The accelerator pot is out of adjustment has damaged wiring or is bad.
S/N F108V08967U, CODE 13, WHEN IN OPERATORS SEAT WITH HAND BRAKE RELEASED, NOT TRYING TO OPERATE FORWARD OR REVERSE CODE 13 COMES UP. THIS UNIT HAS THE MONOTROL PEDAL. CODE 7, WHILE ON SEAT TRYING TO GO IN FORWARD OR REVERSE CODE 7 COMES UP.
can you give us more information?
any errors other than 13 showing on the display when you try and drive?
what is the units serial number?
any other symptoms?