So it’s an E46 then.
I don’t know what you have done to it so far, but if you are replacing like for like pattern bulbs it shouldn’t be a problem. The only possible problem could be the bulb blown indicator on the OBC might not work with LED bulbs.
It sounds like you may have dislodged the earth wire on the back of the headlamp unit.
LED bulbs are polarised, that is to say they only work one way round. Normally they have a red dot or something like that to show which is the positive terminal.
What you may have done is put one or both in the wrong way round and created a return path to earth through the indicator bulbs, coupled with a bad or missing earth that would give you the sort of problem you have described.
Go back to scratch.....refit the original bulbs and test everything..............then fit one of the LED bulbs only and see if it works, change it round if it doesn’t.
Note which way round it worked, then remove it and do the same to the other side.
Then fit them both.
If that still doesn’t fix it, then you need to be looking at the cars wiring for a bad earth. Or a short.
