[Doug Just Doug]

I have the factory 12V outlet. I'm using a flush-mount dual USB adapter in it (I have a rubber dummy plug currently in the unused slot), and am powering my Garmin XT GPS using this coiled cable with 90-degree plugs: https://www.amazon.com/gp/product/B07L7R8YMD/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1 The GPS sits on a SW-M mount over the clocks. There is no interference with anything, and it hasn't been affected by rain (although the set-up isn't strictly waterproof.)

 

[Doug Just Doug]

Does that send your GPS to data mode?

Never has yet. It's been working properly and glitch-free since I set it up a year or so ago.