Voltage drops when turn on electric fan

="TrailBeast, post: 1971262837, member: 19664"]Adding the relay will add a little bit more drop actually.

If this is 12v at idle I wouldn't worry about it.
If it's 12v max with the fans on something is wired to lightly and it can't get the amps through it that it needs to keep up..
I dont see how! Either a Alt problem or a Regulator problem.