Mk3 focus st dipped beam bulb fault

[Pedmk3]

Hi my driver side dipped beam bulb blew the other day so i changed the bulb, i checked the bulb everything worked fine until i started my car then this caused it to blow again so i replaced that bulb checked it and it was fine until i started the car which made it blow again, both have now blown when i started the car. I have tried changing the bulbs with different makers just incase it was due to the bulb. Any ideas?

[Ryan_Tango]

Are you being careful when placing the new bulb in? I know on halogens you're not supposed to touch the bulbs glass as it can cause them to blow straight away.

[Pedmk3]

Ye i always use gloves and never touch the bulb, they light up until the car is turned on then they blow

[biff55]

if you've got HIDs then probably the ballast.

if you've got standard halogen bulbs then possibly damaged lampholder or a short between live & the chassis on the wiring harness to the headllight.

we can rule out overvoltage spikes from the alternator as this would blow both headlamps.

my moneys on the lampholder.

[flynnthomas78]

This problem usually happens because of the faulty ballast or bulbs. In my case I replaced bulbs which I got from an online store, I would suggest you try these ones or if you had tried something like this before, so replacing ballast would be a better option.
Here’s the link of bulbs: https://xenons4u.co.uk/h7-55w-super-white-xenon-effect-headlight-bulbs.html