The Aux/USB combo port is for the Y-cable connector of the early generation smartphones (iPhone/iPhone 3G) of that year 2008.
Your, iPhone 7+ needs a different kind of Y-cable. Once you get that, it should work. Good luck!
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2010 BMW 335i: Monaco blue metallic/Premium+Sport Auto-Steptronic, BMW PE, Cobb Stage 2
2005 Mustang GT: Redfire metallic/5-spd/Ford Racing (Axle backs, silver Bullitt wheels)/K&N CAI/ Diablo Sport Predator Tuner
1997 Toyota Corolla
1983 Mercedes Benz 380SL Roadster