Wiring old Bargman tail lights

[54fuselage]

Without questioning it before, I rewired the Bargman no. 7 taillights last winter with two bulbs, one of them with two filaments. The only reason I did this is because it was the arrangement originally installed. Now I'm wondering why it was set up that way. Shouldn't I only need two wires?

[HowieE]

It is hard to say without testing the fixture, so lets test the fixture.

2 filament bulbs have both the parking light and brake light in them. What you want to do is with a 12 volt battery test each wire to the + terminal of the battery while the fixture is attached to the - terminal of the battery. The brighter light will be the brake light and the dimmer will be the parking light. Now that you know what the fixture is set up with you can test the trailer wiring, with a test light or meter, to see which wire is brake and which is parking light.

The fixture is grounded through the trailer body when installed.

[markdoane]

In olden days there were three wires for each tail light. One was the brake light, one was running light, third was turn signal.
In todays modern vehicles, the turn signal and brake light are the same bulb.

[54fuselage]

Thank you guys! Both very helpful. I'm rewiring the entire AS, so it was confusing to not find a brake light wire for the 7-way but that answers it. Perhaps I'll just pigtail the two wire socket to utilize both filaments, and if one blows the light will still work.

[HowieE]

You do not want to combine the 2 wires, brake light and parking light, to one connection. Keep the parking light, the dimmer bulb, separate. You can connect the brake light and signal light wires, as they are controlled from the TV and now a days the same i almost all TVs.

Connect the TV and test the wires on the trailer for these functions.

[54fuselage]

I should've clarified, thanks Howie that's what I had in mind. In my supplies I found a couple extra single wire sockets, so I installed those. Everything came out beautifully and all lighting works great!

Was able to find glass fixtures for the side marker beehives.