VESPA GTV 250 i.e. 2008 Service Station Manual page 186

Injection
Check the presence of fixed voltage between the
grey/black cable of the remote control base and
earth. If there is none check the continuity of the
grey/black cable between the fuse box (No. 3 10
A) and the remote control base.
N.B.
CONTINUITY TESTS MUST BE CARRIED OUT WITH THE
COMPONENTS DISCONNECTED. (RELAYS, CONTROL
UNIT, FUSES ETC.).
INJEC - 186
Vespa GTV 250 i.e.