Speed Twin 1200 Indicator Issues

Last couple of days have found that the indicators don't always work as I am riding along. Everything works when I start off but after a mile or two if I press the indicator button to the right either nothing happens or the indicator light on the clock flashes once then nothing. I have sprayed inside the control box with GT85 and wiggled the button. Tried tugging on the wires from the indicators to detect a intermittent circuit but to no avail. Any ideas anyone, a new switch box is over £200 and I don't want to buy one if that is not the cause.

 

not sure if the problem starts with the left as it does with the right but either way once it refuses to work neither left or right works until it decides to.