Good Place To Put A Fuse Tap on a '21 Cascadia

Does it have the overhead "compartments"? Typically there's something in there.
Pop the trim off & you'll see wires for a radio.

Not sure if it's a universal feature on newer trucks but I did an install on two Peterbuilts that the owner said nothing was modded as far as he knew.

 

friggin dark in there,, the wires are easily overlooked without a flashlight. OP may even find antennae connection in there as well

 

Does no one introduce themselves anymore?

No good morn' or how the hell are ya, just walk in and expect an answer.

But so that I am not a complete dick, I looked up your fuse box, and in less time than it took you to type the question, I found that the fuse panel cover will have the diagram on the backside of it, find an empty fuse slot and test which side of the slot is hot, tap into that, or junction a fuse to the radio, etc.

Sincerely,
~Crotchety Old Skooler

 

Funny part is since the opening was quite large & that being my first big truck install, I thought it was just meant to hook up then slide in(all wires inc. antenna/ext. speakers/power were present), maybe put some Velcro on the bottom to prevent movement.
Wondered why the owner was so adamant about using what looked to be slots for log books or maps vs my usual mounting method with a bracket.

Then completely by accident I hear a pop & my stomach dropped, now imagining I broke something, big bucks out of my behind for big parts.

Just the fascia popping off & the truck telling me "Hey dummy, there's a RIGHT way to do this!"

Talk about a feeling of relief washing over me. Thankfully nothing broke & the install looked great.
It was a Ranger RCI-something which immediately set a fire in my mind saying "Enough with the 980, get something like this."

Still need to reach that level of bells, whistles & bandwidth but for now the Galaxy is doing the job. Definitely missing SSB capability.