dull light

i have a 1994 2000cc auto passat estate and one of the front indicator/turn lights is twice as bright as the other one i have renewed both bulbs and checked voltages anyone got any ideas

How about the grounds? I believe both go to the battery negative terminal. There should be less than 1.5 Ohms resistance between the socket (brown wire) and battery negative.

Is one just aimed different then the other? Thta could significantly change the look of the output.