Originally Posted by John long
It appears to me this will work but I am not sure why you are doing it. Is this a way of wiring turn signals because you are not running a conventional turn signal switch?
This is a fairly common problem encountered with 3rd party wiring harness installs and custom taillights as revealed by Google searches.
If you have one dual filament bulb on each side serving as parking light and then the brighter filament serving as brake/turn signal, you have 1 wire too many to hook up to your bulb on each side. The most common circumvention is the one I took to start with: using a trailer harness adapter designed to work with towing vehicles that have a separate circuit for brake lights and turn signals (mostly imports - eg this type of adapter: Hopkins/Import tail light converter (48845) | Tail Light Converter | AutoZone.com
). This allows the same bulb (usually an 1157 or similar) to serve the dual purpose.
My particular situation was complicated because I had installed bedroll lights into my 53 Chevy's truckbed. Due to a local law the turn signal must be within X distance of the brake lights meaning I couldn't just designate one pair of lights as brake and one pair as turn signals. Sure I could have ripped out the bedroll lights but really liked the extra illumination from the rear.
As I have stated a few times, the adapter method worked, but they aren't exactly long lasting hence my desire to take a better route of using relays to accomplish what I needed.
Of course if you know of a simpler method, I am all ears but I sure haven't seen a solution anywhere.