My 3rd brake light install. Car is still 6 v so I bought this DROK 6v to 12v convertor. Pretty neat little package that says it puts out 10 amps. Haven't checked that out as I don't need that much for the GM 3rd brake light. Been testing it for a week & so far all is good. DROK says that you can run your radio off it. I don't run a radio in the roadster as the Brockmans & wind are music to my ears. Cost was less than $30.