Brake\Tail\Turn Combo Light Circuit Question

Hey folks, planning out the wiring for the rear lights of my truck and ran across something where I think I might be missing an obvious answer. I am using a Haltech Nexus R5 and have HCOs assigned for each of these items: brake lights, left turn sig, right turn sig, and running/tail lights. The truck is from the mid 90's so it only has a single 3157 for stop, tail, and turn. Obviously brakes are just both filaments energized. If I were to run my brake light HCO in to both the rear tail light circuits and each turn signal circuit I'd have to run diodes on all of those circuits to prevent back feeding correct? Is there an easier way that I am overlooking? I attached a quick drawing to, hopefully, better explain what I am thinking. I would LOVE a solution with no diodes!

Had a further think about this, I am just going to use DPOs for the turn signals at each corner. Running LEDs so the amp draw is well under the 3A stated capacity. For the marker/running lights I'll keep the HCOs, but split them up circuit-wise by front and rear. Then the rest like brake lights and hazards can all be done with logic in NSP. Bonus is I freed up 2 8A HCO!

You may be mis-interpreting the tail-lightfunction. Normally these use the low wattage filament just for tail-lights, the higher wattage filament has 3 operating conditions - 1/ indicator only where the current in enabled by the indicator current and flashes 2/ brake light only where the circuit is energised by the brake application and 3/ indicators with the brakes applied where the indicator turns off the brake light to provide the flash.

If you have a search, on these forums, you will find this problem has come up several times before in threads, which should give you more information to work with.

The two filaments are low and high brightness.

The tail lights are the low brightness filament.

The Stop and turn are the high brightness filament.

The only time both filaments are powered is when you have the tail lights on AND you have the brakes or turn signal on.

If you have brake or turn signal on, the low brightness filament remains off.

So, there's no need for the diodes, just proper setup in the ECU/PDM.

I don't entirely follow your diagram, but it's over complicating the circuit.

You will need 3 wires, tail lights, left turn/brake and right turn/brake, tail goes to both tail lights, and any additional low output lights, like the license plate light, the left and right wires will go to the high brightness filament on each bulb.

No, Chris, see part three of my post.