Audio Non Geek needs assistance

I was (and am again) thinking the same exact thing. I have a Kenwood in there now - with water damage that finally looks like it is dying. But I find I pretty much ONLY use my phone through Android Auto for Nav and Music. I was thinking of going the same route - BTC only. But I have not found a "screen only Bluetooth Controller". Closest I found was the Kicker KMC5 but again, that's just a smaller-than-2DIN head unit with AM/FM/BT/etc for the same price as a full big unit.

I have not yet found a truly water-proof Double Din unit. The Boss Audio from Slingmods that says it's marine really isn't - it's splash resistant only on the front display, not behind with the electronics. The Sony XAV-AX Series while not officially waterproof, has been shown to be fairly resistant to water, even videos of folks hosing it down with water and it still working. (And truthfully, my Kenwood, while not marine, has done pretty good a couple times getting caught in HEAVY rain.)

Regarding what's under the dash to use - forget it. About the only thing you can really use is the power wires. Slingmods and others sell the wire adapter kits so you can install a different head unit, but pretty much nothing stock will be of much use. Just figure you're starting from scratch whatever you do.

If you want to display the volume of the in-vehicle music system, I must admit I know nothing about the Vanderhall's sound setup, but I'd recommend contacting Vanderhall and asking if any other customers might have contacted them about a similar solution.

What music source are you currently using? If you're using cell phone as a music source, there's probably an app that shows the volume level. An alternative would be to use a stand-alone MP3 player with a Bluetooth connection to your Vanderhall. In either of these cases, I recommend setting a fixed volume on your Vanderhall's sound system (check with Vanderhall to see if that's possible if the info isn't in your owner's manual) and then use either the app or the MP3 player's controls to view the song title, advance/reverse position, select the next song, display volume, etc,. If using a MP3 player, I'd recommend selecting a unit that allows you to display whatever info you're interested in. This might make a busy display, but you can hopefully select a unit that meets your desires/needs. A quick glance thru the Google Search results from the link below showed a variety of units in different sizes ranging from the size of a large wrist watch to larger units that would most likely be carried in a shirt pocket, but even a larger unit might be held on the dash using some double-stick Velcro tape.

This Google search may have a solution - https://www.google.com/search?…awKHbGzDxcQ_AUoAHoECAEQAA. It's possible to get lost in all of the info the Google search can produce. Selecting ALL for the search results will provide a series of pictures that might help you identify a possible candidate which you can then research for more detail. An alternative would be to Select Images for the Search results which will provide a very broad selection of possible candidate music players.

Funinthesun - I did a little more research and noticed that some of the music players I found wouldn't meet your needs since they rely on a built-in FM transmitter to get the audio to an FM radio and your Vanderhall doesn't have an FM radio. When I first saw this, I thought the unit itself had an FM receiver and then used Bluetooth to send the music to the vehicle. Just make sure that any music player you might be interested in uses a Bluetooth connection to transmit the music to the Vanderhall.

Some of the music players have a rotary volume control. If nothing else, a dab of paint on the rotary volume control would provide a visual indicator of the volume.

Just another thought: How about using your iPhone/Android as your display then use one of the many waterproof bluetooth controllers to then control the volume. You could set up a mount with USB charging for the phone and then just use the BT direct to Amp to control the volume/playback.

The problem is finding a BT controller that has a display. That's why I suggested using a stand-alone player, but finding one that shows enough info is not easy.