What you need
10 mm spanner
W5W bulbs
10 minutes
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Start by popping the bonnet, and undo the 3 10mm bolts on top of the headlight. Now pull back the big cover and underneath the high beam there should be a cylindrical bit as seen underneath.
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Pull it out by squeezing the 2 plastic tabs. The bulb can simply be pulled right out, and just push the new one in. The bulb in the picture is the old one.
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Now simply push the cylinder back until it clicks, put the back cover on, the 3 bolts and do the other side, rinse and repeat. The left side actually is easier to do than the right side, in my opinion.
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If you did it right, here is the result.
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