[HillbillyHydroNVinyl]

The bulbs are hi/lo headlight LEDs with Amber low beam and 6k white high beams.
I used a 5 pin relay to add the switchback function. The relay +VDC is connected to an ignition +, grounded to chassis, normally open to the amber, normally closed to the white, and the trigger wires to the turn signal +.

You'll need 1 relay per side.

 

[dezldave961]

Pretty cool. Good work!

 

[HillbillyHydroNVinyl]

Thanks, the standard automotive 5 pin relay worked fine but I think I'd use a solid state if I were to do it over. With the new LEDs the reaction time is much better and durability over the long haul is supposed to be better, though in 35 years of driving I've never had a relay fail. Solid State is also quieter but the new 5 pin I used wasn't particularly loud so I guess it's all relative. If anyone needs a diagram I'll sketch one up.

 

[HillbillyHydroNVinyl]

Total cost was less than $40 including the bulbs. I believe they were 9008 hi/lo