citroen c5 regd 2003 head lights keep going out intermitently?

Ive got the same problem and have not been able to find out whats wrong

Ive had my C5 for 9 years my headlight bulbs blow approx 3/5 times a year...its so annoying because they are a pain to fix never mind the cost. Garage cant help me..they just say buy the expensive bulbs (which ive tried and no difference what so ever)>

Duncan Gould
May 2011