Hello everyone! Looking for some help. My wifes 2010 M6 has the halogen headlight assemblies. One of her H7 low beam bulbs burned out and were good and bright at night. I opted to just replace them both since the good bulb probably wouldn't be far behind burning out too.

We went and bought new H7 low beam bulbs from a Mazda Dealership. After installation, her light's are so dim it looks like they're not even on and she can't see without using the high beams. I can't figure out what has changed. Has anyone else had this experience?

 

Have you checked you bought 12v bulbs and not 24v?

Also, from memory the H7 bulbs fit in an adapter, these often melt and can cause high resistance.

 

Yes, they are 12V/55W H7. I did discover that when replacing if your not careful the bulbs won't seat correctly in the plastic adapter which will cause them not to be far enough in the projector of course. I thought I'd try cleaning the projector lenses with rubbing alcohol but again, the low beams were bright before one burned out.

I do know they're getting the correct voltage however I'll check the resistance to see if that's high. I didn't even think about that being the adapters are plastic but anything is possible with electrical and you have a very good point. I'll check that before I remove the headlight assemblies for projector lens cleaning. Thank you sir!