I have all new wiring in my 69 Roadrunner, and I'm getting it all installed and dialed in. So far everything works, except the horn but I have a concern about the tail lights.

I noticed that the filament that lights up when the running-lights are on is extremely bright and the brake light / blinker filament in the bulb is fairly dim in comparison. I'm pretty sure it supposed to be the opposite. Is there an easy fix? Did I mix up the signal somehow? Everything is "plug and play" so I'm not sure where I may have made a mistake.

Is it possible the issue may be in the steering column wiring? I matched the colors coming from the steering column (rebuilt and rewired professionally) to the new under-dash wiring harness. Not only do I have this brightness reversal issue, but my horn doesn't work. Although if send 12 volts to the right wire in the harness the horn is activated.

Just thought I'd throw this out and see if anyone has a possible solution or suggestion.

Thanks!
-Dan

Not exactly sure how your harness was wired but most horn buttons provide a path to ground for the relay. Sounds like your taillights are wired backwards as well
Gus

Sounds like the "brake/turn" and "running light" wires were reversed somewhere in the harness. Or bulbs installed backwards which should be difficult to do without damaging something. Easy fix right at the socket if that's the case.

Definitely check the circuits with a test light. Looks like all the rear running light circuit wiring is black. They originate as a single wire running to the rear of the car before branching off to the individual lamps. Right turn/brake light is brown. Left turn/brake is dark green. If it was crossed up further forward, all the running lights on the rear should also be not right. All this stuff runs through an 8 pin connector behind the left kick panel.

3 wires run it all. Both sides doing the same thing? Front turns OK? Tag light OK?

The black wire on the horn relay runs through the bulkhead to the turn signal switch connector and should go to ground when the horn is pushed. That can be checked with a test light. It should also blow the horns when a ground source is touched to that pin on the relay. Constant 12v needed on the other pin.

X2

Just wanted to post an update. I took a closer look at the tail lamp bulb sockets. Keep in mind this is a new harness. I was able to turn the round contact disk inside the sockets with a small screw driver which effectively reverses the signal to the bulbs (which only fit in one direction) -problem solved. I think the harness manufacturer installed the contact disk backwards, but it's a super simple fix. Thank you for the suggestions, it helped solve the issue!

Sucks when you have to fix new parts, but it happens.

Wrong bulbs can also do that, I believe you should have 1157 bulbs in there, if so then it's fixed.

And 2157's are a bit brighter.

Thanks guys. I do believe they are 1157s.

I put these in my road runner. They are supposed to be the brightest incandescent bulb you can buy. I haven't seen how they work yet as the car is in the shop and will be for at least 2 more months. https://smile.amazon.com/gp/product/B00BFDIN0K/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1