If you can tell me how affecting the air flow can have an effect on the electrical system, then we will just have to re-evaluate science as we know it.
It appears to me you are falling into the same trap I did when I got started. If I did a mod and a customer got a ticket for no tail lights, it was my fault. So, I fixed it.
When I have a customer like that (I can spot them now before I do any work) I simply will not serve them-EVER again. You have enough of a hurdle to overcome learning the tech, Carlos. You do not need problem customers.
How much did you charge?
I bet it was "Nothing."
Well....?