I thought my boost switch didn't work due to the switch or solenoid. Turns out the light on the rocker was bad. I ordered a pack of 2721s and replaced it. Boost is still not working but that's due to bad house batteries that I need to replace.
I ended up checking all the rockers lights, 3 were bad. Two more packs of Hella 2721s showed up. Super easy to replace. It's 6 screws to remove the bezel and gently pull up on the control board. Mine had plenty of wiring loom so I could lay it on its side. Some lights are activated by turning the headlights on, fyi. Retarder works I know since I use it driving.
The heated mirror required me to lay down then pull the light out. Once you do the others you'll see how it goes.
Now I have a Christmas tree)). I think most of dont drive at night but it's nice to have at dusk, dawn or even parked to turn on the floods for example. Sometimes it's the little things...
Ya... best not let stuff slide. One thing turns into 2 and then 3 and so on. Trouble is with an RV it's always something so there's that.
Now if i can just practice what i preach.