Interesting that brake light goes out when turn signal is on

[19llhpb]

I’m sure many of you know this but I didn’t see a thread on it unless I missed it. Can’t believe I didn’t notice before but after following my wife home as she was driving the Ram I noticed the brake light would go off on the side that the turn signal was active. When I got home I tried the flashers and obviously the same thing, neither brake light would light with the flashers on. I know it is to make the turn signal more visible. I know most new vehicles will have the DRL’s go off on the front of the vehicle on the side that the turn signal is active obviously so the signal is more visible but I haven’t seen it on the rear of a vehicle before. Just thought it was interesting. Can’t believe I just now noticed it, but then again, I am generally driving my truck and not following it!

 

[Jordan2929]

I noticed it too when installing my magnum headache rack with the rigid lights, it made the wiring part a real PITA.

 

[19llhpb]

I noticed it too when installing my magnum headache rack with the rigid lights, it made the wiring part a real PITA.

I was wondering myself how this would affect the aftermarket light setups such as headache racks like yours, tailgate light bars, exc.

 

[Jordan2929]

I was wondering myself how this would affect the aftermarket light setups such as headache racks like yours, tailgate light bars, exc.

Most people would just hook into the trailer plug harness, I thought about this but after some testing there was a very noticeable delay between the truck and trailer plug. That would’ve annoyed the hell out of me, so I took the not so easy route.

 

[Electrical]

I can't help but wonder about the internal Mopar discussions on this. The Durango has sort of an opposite issue. The turn signals are red... and I seem to recall Ram making a point about the new truck turn signals being made amber for better contrast. On the Durango, the red turn signal is very hard to see in the presence of the very bright rear running lights.

Example picture from the internet:

 

[19llhpb]

Most people would just hook into the trailer plug harness, I thought about this but after some testing there was a very noticeable delay between the truck and trailer plug. That would’ve annoyed the hell out of me, so I took the not so easy route.

Yeah, I installed a couple small led lights under the tailgate when I first bought the truck. Just a couple 12” bars on each side, skipping the center. However, I only connected the regular and brake lights, they are only double function and not triple with the turn signals so I never noticed it even when hard wiring these cause I didn’t even bother with the turn signals. These small light bars are actually what got my attention and not the factory brake light. Noticed the light bar brake light would go out with that side turn signal on, when I first saw it I thought my lights were screw-in up, but that’s not the case.

 

[19llhpb]

I can't help but wonder about the internal Mopar discussions on this. The Durango has sort of an opposite issue. The turn signals are red... and I seem to recall Ram making a point about the new truck turn signals being made amber for better contrast. On the Durango, the red turn signal is very hard to see in the presence of the very bright rear running lights.

Example picture from the internet:
View attachment 15628

Personally, I have always liked the rear lights on the Durango and Charger and I would agree, the regular lights are so bright that sometimes the brake lights are hard to see. Looks a little odd on the rear of my truck since my tailgate led’s are hard wired and the bar brake light goes out on the side of the active turn signal. I could hard wire them together so the brake lights are always working on both sides regardless but then this would cause double the volts/amps to each side when turn signals are not on and probably cause some other issue. The electronics on newer vehicles are obviously so much more complicated and sensitive than they use to be. Back in the day on my 80’s and 90’s pickups I could put lights anywhere and everywhere and wire them up however with no problem!

 

[Old Ray]

Hum, not sure on newer vehicles, but turn signals have been around since the 1950's and hadn't changed maybe until LED's. The original ones did not have three circuits or functions, they had two with a trick, there was the tail/park light circuit (low light filament bulb), and the brake light circuit (high light filament bulb), when turn signals came out the brake light circuit to the side that was turning was interrupted/cancelled and allowed to flash by the turn signal switch. When import cars started showing up with separate independent amber turn signals lights along with red brake lights (three circuits) things changed, especially if wiring to a two circuit tow trailer, I think it matters on the number of rear lamps (circuits).

 

[19llhpb]

Hum, not sure on newer vehicles, but turn signals have been around since the 1950's and hadn't changed maybe until LED's. The original ones did not have three circuits or functions, they had two with a trick, there was the tail/park light circuit (low light filament bulb), and the brake light circuit (high light filament bulb), when turn signals came out the brake light circuit to the side that was turning was interrupted/cancelled and allowed to flash by the turn signal switch. When import cars started showing up with separate independent amber turn signals lights along with red brake lights (three circuits) things changed, especially if wiring to a two circuit tow trailer, I think it matters on the number of rear lamps (circuits).

Yep, have a lot of equipment and older trucks around here like that. Same bulb with two filaments, one bright for turn and brake and the brake would be interrupted for turn as you said, and a less bright filament for regular light. Have had vehicles also, for example, an older Honda Accord which had a separate amber colored rear turn light designated for turn only. The brake on the turn activated side would still light up. They were all older bulbs and not LED, they were just all separate.