OK, Here goes on a nidiots test for blinkers.
you will need approx 4 ft of single core wire bared at both ends.
connect one end to the battery positive, making sure first that the battery is charged.
On each blinker there should be a black wire exiting from the stem which should have, if its original, either a light blue "sleeve" or an orange one near to the "bullet.
Disconnect this wire from the loom on each blinker in turn and connect the bare end of the 4 ft wire to the bullet MAKING SURE IT DONT TOUCH ANY METAL!!!
If the bulb dont light check, in order, bulb and socket then the ground
When you have all four working NOTE:- THEY WONT BLINK! reconnect to the loom
Go to the blinker relay which will have two or three wires on it. Having noted where they are connected disconnect the relay and connect together, using the 4 ft wire that you have DISCONNECTED from the battery, the grey and the black wires.
With the ignition turned on you should now get a steady light (No Blink) on one side at a time as you opperate the blinker switch--only one side means switch duff, nothing at all could be switch or loom..
When you have corrected any faults reconnect the relay and if it now dont come on or blink the relay is duff
Thats the complete test but it ASSUMES (making an ass out of u and me) that all the blubs are the correct wattage (21 wat) and that the loom is in good order