so ive been putting off this install for like two months now and finally pulled the trigger on mounting my 2m/70cm dual band in the truck. got a yaesu ftm-400 and a diamond nmo mount on the roof, but im kinda stuck on the best way to get the coax inside without making a mess or letting water in.

i found what looks like a factory rubber grommet near the firewall on the passenger side but its already pretty packed with factory wiring. didnt want to just shove the coax through and call it a day without asking around first. some guys at the club said to drill a new hole and use a pass-through grommet, others said just find an existing one and carefully work it through. truck is a 2019 f150 if that matters.

also curious how people are handling the coax run inside the cab — under the carpet, along the door sill, or just zip tied under the dash somewhere? i want it to look somewhat clean but im not a professional installer by any means.

I did almost the exact same install on an F150 a few years back, slightly older model but the firewall situation is pretty similar. I ended up finding a grommet on the driver's side that had just enough room to squeeze an PL-259 through if I removed the connector, ran the coax, then soldered it back on inside the cab. Kind of a pain but it works and looks factory.

For the run inside I went along the door sill on the passenger side under that plastic trim piece, popped it off carefully and tucked the coax under there, then came up under the dash. Took maybe an hour total and you cant really see any of it. Just make sure you leave a drip loop outside before the coax enters the cab so water doesnt wick in.

yeah the drip loop thing is important, learned that the hard way on my jeep lol. also on the f150 specifically there's a pretty well known spot on the passenger firewall that a lot of people use — if you search the f150 forums (not ham forums, just the truck forums) you'll find pictures of exactly where it is. saved me a ton of time when i did my install. good luck with it, the ftm-400 is a great radio for mobile, display is super easy to read while driving