Forgive me if this has been asked or addressed somewhere before, but does anybody here know of a documented or undocumented wire we can tap for 12v as a dimming line in an '05 Prius? My understanding is that the dimmer signal for the stock and JBL radios comes from the CANBUS, so isn't available to use for an aftermarket radio. Obviously, I cannot tap into that for this purpose, but I was wondering if there was a line, like from the dimmer wheel, I could tap as an equivalent signal.
Easiest way to do it would be a piggyback connector from the taillight fuse under the dash to your dimmer (usually orange) lead on your unit. Use a meter or test light to find the downstream side of the fuse for the piggyback. Pull the fuse, turn on the parking lights and probe both sides of the fuse socket. Upstream side will show 12 volts, the downstream side will not. Route your wire carefully and you're ready to rock n roll.
Thank you very much! I'll see about doing that once I have time, and I'm up for tearing the dash back apart. This has been my one major annoyance with the head unit I'm using.
Is the question about bringing the taillights-are-on signal to the unit, so it knows when to switch from day mode to a single preset night-mode brightness? Or is the question about bringing the panel-dimmer signal to the unit, so its night-mode brightness will adjust with the rest of the dash?
Specifically the first case, I know using the panel dimmer would require a lot more work, and likely wouldn't be supported by the headunit in question (currently a Dual DCPA813, needed something cheap, was annoyed by the bad quality of using a tape adapter), it'd almost assuredly need something a lot more high end, or something more custom to be able to do that. I know it's a lot more realistic to supply the dimmer line 12v and just have it switch when the lights are on, it'd lead to some annoyances on occasion, but I just want it to know when to go to minimum brightness vs maximum brightness, and hopefully send my phone a signal to switch to night mode on the maps, since of late, neither Google Maps nor Waze likes to work quite right in that regard.
There were adapters made back in the day that weren't tape adapters. DICE Electronics was one of the sources. I had one in my gen 1, which had only been advertised for gen 2*, but with a little wire harness tweak it worked fine. It plugged into the back of the stock headunit the same way the CD changer or minidisc changer would, and came with a Y cable so if you already had the CD changer you still had it. The DICE box gave itself the AVC-LAN address of a minidisc changer, which wasn't offered in the US, so it didn't collide with anything here, and you could select your CD or your "minidisc" from the touch screen. The DICE box I had would connect an old iPod or a regular wired aux input (which you got, if I remember right, by choosing minidisc 6 on the touch screen). Minidiscs came with track title information, so the box was able to show the track titles from the iPod. I have not looked in years to see what the market for that sort of adapter contains now. Because that kind was directly wired at the back and did not go through any funky tape-head interface, the audio quality was great. * there had only ever been like 52,000 gen 1 Prii sold here, so they got overlooked for a lot of product testing
