I'm trying to put together a circuit to drive an LED module with high and low inputs and a common ground from an AC supply with one common leg and one leg ("low") that is switched to a 3rd wire ("high"). The "low" input is always on, and there is a switch that connects the "high" leg to the "low" leg. (it's a tail/brake light for a vehicle with an AC electrical system, originally it was an incandescent bulb with 2 filaments).
What I'm running into is that there does not seem to be a simple way for the high LED to be off until the switch is pressed, and then come on in full wave rectification. What I got on my first attempt was simply switching the high LED from half wave to full wave, which is certainly obvious in hindsight but was quite disappointing when I discovered it. The circuit I tried first is thus:
The best way I can find to solve this issue is with a DPDT relay, like this:
I'm not opposed to using a relay, but I'm very space constrained in this application and finding a very small one with an AC coil that's of reasonable cost seems problematic based on my limited searching. I'm by no means an EE, so I'm hoping that there is some obvious solution that I'm missing here, or a fairly simple circuit design that I could get in a small custom PCB.
The specs are as follows:
Low LED draw: 90mA
High LED draw: 450mA
Nominal voltage of both AC and DC systems is 12V
AC frequency is variable with RPM, as it is generate by a stator.
Thanks in advance for any suggestions!
Edit: Solved the image issue by slightly cheating with forum image urls.