The easiest and cheapest way to fix it is to wire in a resistor to each indicator.
I bought 10 watt 10ohm resistors from Maplins - they were about 40p each!
You will need one resistor for each indicator.
The resistor will need to be connected ACROSS the two wires that feed into each indicator.
Use a soldering iron/solder (from £5.99 at Maplins!) to connect the resistor to the circuit, and use some heat shrink (thin plastic stuff
) with a hair dryer to seal it all afterwards - alternatively, you could just use insulating tape.
HTH
Matt