Renault Wind indicators

I have gone to replace the rear nearside indicator bulb as it is not working and the front and side bulbs are flashing in double quick time. However the bulb looks fine and two good replacements don't work either. Very puzzling!

The other bulbs will flash twice the speed while ever the rear one isn’t working.
I would try cleaning the contacts up with a little Emery cloth and make sure the bulb is making good contact.
If in doubt, swap the rear drivers side bulb over that you know is working to see if that works just as a test.