[4Wheel]

There is usually a soft rubber bulkhead "grommet" on the Drivers side in front of the junction block where the wire harness passes, should be able to get "one more wire" through nestled up against the harness.
Like Brians idea of placement, where it counts.
There is so much turbulence around the windshield and cowl areas no telling where that air has been.

The area behind the mirror is not good there is a high vacuum there and will draw air from through the side window seals. I count on that when I am eating pistachios.