Another turn signal dilemma

[Varhalla]

I'm a long time owner of a 427 SC who is finally on the home stretch to completion. I'll bore everyone with my build details later.
I completed the wiring connections on the lamps this weekend and everything seems fine, headlamps high & low, park lamps, brake lights, emergency flashers. Everything is bright and dim when it should be so I don't suspect any bad grounds.
Here's the bug. When I activate either the left or right turn lever, all four corners flash. I've gone over the connections again & again and find no issues there. I did convert to the rectangular lamps but the problem persists even with these disconnected.
This will not beat me but I'd appreciate any information the forum may offer before I tear into the hardware.

[RJacobsen]

When you apply the brakes do the front turn signals light up also?

[Varhalla]

Yes they do. I didn't notice that before I connected the rear lamps. Yout question tells me you may have the answer.

[RJacobsen]

When you converted to the rectangular taillights what did you do with the white #28 wire? I have an older 289 car that I am currently reworking the wiring on and I don’t have that wire going to the rear. I am assuming that you still have the taillight converter wired in.

[Varhalla]

I don't have a converter wired in.
I currently have the white wire going to the rear brake light (bright element).
Disconnecting the rear lamps altogether does not eliminate the front turn signals both operating at once. What I'm starting to understand is that the rear lamp wires are somehow critical to the whole operation.

[RJacobsen]

Did your car come with the converter? The turn signal switch is made for use with a European car that has separate turn signals (amber) and brake lights (red), the converter is used to combine and separate the brake lights from the turn signals for the taillights that we are useing on our cars. Because we are useing the same taillight curcuit for both brake and turn we have to separate the two or we will have front brake lights as well. I think that you may have two problems, 1 is that you need to have a converter installed and, 2 is that the white wire (#28 from the brake light switch?) that you connected to the taillights should be #4 (green) for right and #5 (yellow) for left.

[Varhalla]

The car did not come with a converter and was a basic roller. It could be that it was simply not included but more likely it was wired for the round lamps.
It looks like I'm in for a converter installation so any advice on the type or brand would be appreciated in addition to the help you've been so far.

[RJacobsen]

I don’t think that it will matter brand wise. The converter that you need to look for is a trailer wiring device for vehicles with separate brake /turn lights to connect to trailers with combined brake/turn lights. You would wire the right and left turn signal wires from the turn signal switch and the brake light wire from the brake switch to the appropriate wires on the converter, you then should have a separate right and left brake/turn wire from the converter to connect to the tail lights. This is a pretty basic explanation remember that you also need to have the front turn signals wired separately from the switch as well as the emergency flasher switch. Did you get the wiring manual with the car?

[Varhalla]

Got it. I'll be picking up a converter asap.
I did get the wiring manual with the kit and have not deviated in any other way from the directions. I have a three way (off-on-on) for the parklamps/headlamps and this works fine. I have a two way (off-on) for the hazards and this works fine also. Since they are already wired independently per the instructions, I couldn't figure out why the signals all operated simultaneously even without the rear lamps wired up. It's apparently tied to the rear lamp wiring.
I assume that once the converter is wired into the rear that the turn signals will operate independently on all corners.

Many thanks. You've got a beer coming if you ever get to Pensacola, Fl.

[RJacobsen]

You might want to double check the existance of a converter. I think the factory wire harness would have had one prewired in. If you connected the white wire (#28) with the green (#4) or yellow (#5) you could have the turn signal switch acting like another hazard switch. The White #28 is for brakes only and has to run through a converter or it becomes connected to front lights through the turn signal switch.

[pgermond]

Rod,
Sounds like that wiring harness manual has been useful :)

[RJacobsen]

Rod,
Sounds like that wiring harness manual has been useful :)

A life saver[thumb]

[Varhalla]

A close look at the harness does not show any converter so until if get one, I rewired the four round tail lamps in just for test purposes. I get the properly operating brake lights in the rear. No funny business up front so clearly the trailer converter is in the immediate future.
However, I still get all four turn signals flashing with either the left or right turn lever positions. Stating the obvious, the bright elements on all four corners are getting current simultaneously from a source common to the turn lever.
Epiphany number one. Current flow through the dash indicator lights and their common ground?
Epiphany number two. There is a "common" turn signal connection at the plug between the column and main harness. Suspect?

I should have majored in electrical engineering.

[weaver]

Only the 289 harness needs the converter, your troubles began when you changed from round tail lights to a single rectangular light without going with a different harness. If you can't figure out the trailer converter call me and I will give you our wiring guys phone number.

Alan

[Varhalla]

Thanks Alan. I'll give you a call tomorrow.
The converter looks like an easy install but I don't see it solving the turn signal issues, especially after having wired up the original round lamps without effect.
It looks like a call to the wiring master.

[RJacobsen]

The only common connection for all the lights at once is through the hazard switch, check to see if it is wired properly or somehow on all the time.

[arrowdriver]

I bought my Unique 427 used a few years ago. It was built by Unique in 89 and has the two round liights on each side. In debugging the car one of the items was the brake and turn signal lights not working right and traced the problem to the converter having failed. When I bought a new one I noted that it wasn't rated for the full load of both brake and turn siglal lights so it was likely the overload that had caused the failure. I guess maybe Alan had installed it with one light being brake and one turn but for safety sake I wanted both operating for both functions so replaced one bulb on each side with a LED to reduce the load. You can't replace both even if you want to since the flasher needs the load of a regular bulb to operate.

Hope this helps.

[RJacobsen]

OK now I’m wondering who has what , I have a 289 car build in 92. I’m using a wiring manual dated Feb 2003 for a 427 car. So far the manual I have matches the wiring in the car for everything including wire color and numbers. The only exception is the wiring for the tail lights (two instead of one) and some minor differences in switches. The manual also shows a converter as factory wired and connected into the harness, yet Allan says that the 427’s don’t come with or need the converter and that makes sense given the way the two tail lights are wired. Has there been a change on the newer cars?

[arrowdriver]

I guess if they wired the car to use one light on each side for brake and the other for turn signal then there would be no need for the converter. These converters are really sold to "convert" vehicles that have separate signal and brake lights and enable them to pull trailers that have the bulbs doing the dual duty of both brake and turn signal. You can find them in any reasonably equipped auto supply store.

[weaver]

There hasen't been a change in the harness just the manual, when we sell a 289 kit or a 427 kit with rectangular tail lights we give the customer a 289 harness with the converter, that is the only difference.

[Varhalla]

I've checked the hazard switch. It's factory wired and I even disconnected the wires and separated each to see if it made any difference. The only effect besides having no hazards was that there were no dash indicator lights. All four turn signals activate at once with left or right lever position.
I'm going to open up the column next to check for any obvious issue with the switch.
I also question whether the hazard switch is the only common connection for the four signal lamps as the hazard switch has only a hot wire and the blue turn signal wires, nothing that matches the rear turn signal wires. Somewhere they're all getting power at once.