sterling little gem the make?

You should never leave a mobility scooter outside without a cover which I suspect is the case here and maybe rained and water has got in to the circuit.
First look for a control/fuse box which may be in the battery/motor housing check the fuse/s find one that’s blown and replace it ( get three new fuses, may be the spade type used in cars, so car spares shop will have them. Ensure you get same number on fuse they are also colour coded) so if its 5 then get three 5’s do not use a higher fuse you’ll likely burn the wires out if the fuse doesn’t blow. Check you have wired the ignition properly and have fitted the speed control (fastness) wire back properly. Disconnect the horn and separately tape the wire ends so they can’t short out. Try the ignition and if the scooter doesn’t work or the new fuse blows then either you have wired the ignition wrong or there is something else seriously wrong. You’ll have to get it checked by a mobility scooter mechanic.

Bob uk
November 2013