I have some problems with starting the bike, when turning the key on - all the light turn on

but when to press "start" button the engine doesnt start.
it helped when I kept holding the "start" button and hitting a little bit relay (the thing that have 2
wide cables - one from battery, and another from elsewhere

but now it doesnt help. to start the bike I have to make "short-circuit" (by connecting these 2 cables
for a second)
the only way out is to replace relay?
any idea where to get this?
cheers
greg