Hi guys, I've totally lost my nerves and I'm at the end.

First of all, I want to change the taillights on my 89' Trans Am, I live in Switzerland so they have here the orange Turn Signals, and they look awful, so I bought a pair of black smoked US version taillights.
My problem now is the wiring, I just dont get it. One taillight has 4 chambers, I want that the three red chambers show: Normal light, Stop Lamp and Turning Signal. the 4th chamber shows the white backup light. I know thats not original US. (Original would be only 2 chambers turning signal, not 3).

Alright, now what do I have? My taillight for you in the US is known as the Formula, as far as I know. So I have on each taillight one only-Turn-Signal-Lamp (Amber).

I found a wiring diagram, it shows the "Trans Am" and "others" version. "others" should be my version. My car: If I use the brake, the signal goes directly to the tail light lamp (LH and RH Tail Stop Lamp). If I use the Turn Signal, the signal comes from the Turn Flasher and goes in the Turn/ Hazard Switch, from there it moves directly to the LH and RH Turn Lamp (Amber Light).

The US Version (Trans Am on the wiring diagram) is as far as I know wrong: It cannot work with that wiring, if I would break, the signal goes from Brake Switch Assembly as a light blue cable (WHY IS IT LIGHT BLUE AND THEN WHITE?!) and comes as a white cable in the turn hazard switch. But what happens now with the Trans Am version? How should the signal come to the four chambers? I don't know and the wiring diagram doesnt show it.

Does anyone in the world know what I have to do, that I get the Brake Switch Assembly trough the Turn Hazard Switch and then to the Taillights?
I'm so down with this and I don't get it anymore. Please Help

 

It's very easy. You need to rewire the rear and throw out the brake wire and wire all to turn and ground. Then get a new pin for the harmonica connector under the column. It has an unused empty pin on the wiring side and available column side. It's a white wire one if the first couple if pins. This is the blinker output for brake turn combo. Cut the other one and wire it through the brake switch. Im on my phone and can post a better wiring and schematic if needed.

 

THAT's what you want right? That's one of mine

 

Here is the wiring diagram: http://fs5.directupload.net/images/160106/3lvdlaz5.jpg

@Twin_Turbo, Yes that's it!

 

Thank you, I will try that. I would be very happy if you could post a better wiring and schematic, I don't want to make any faults. Thank you very much.

 

in your pic, see the white wire coming off the column to the long flat black connector? That's the one you need. There's no mating wire on the other side. You need to insert a new pin and wire in the connector pinout opposite the white wire and snip the wire off the brake switch, connect it to this one. This way the brake signal is run through the directional switch. With no directional input all 4 lams will illuminate, with one side the lamps will flicker on and off just normal and when you depress the brake the signal switches it's pulse (normal blinker one is brake light off)

The wiring diagram you have there shows it correct. Snip lt blue and connect to the white on the harmonica by inserting a enw pin with wire (or directly but makes disconnecting steering column more work or use some kind of connector)

That's all there is to it.

 

TwinTurbo, so you are saying the standard turn signal switch and the TA turn signal switch are one and the same? There is another member in a recent thread that wanted to do the same mod but was leery of the under dash wiring. If the switch is the same, then as you stated, just running a wire from the brake light switch output to that connector should work. That is provided the switch is the same for either model and the wire from the switch to the connector is present. For the rear, you could use the TA harness if available or just cut and splice the appropriate wires. Should be pretty simple and not very time consuming then. Thanks for the GREAT info. I'm sure this will help a lot of people to unravel the confusion of this mod.

 

In fact they are the same on most any GM car up to the mid 90s or so, all columns I have ever seen all have the wiring on the column, just not all cars on the mating connector. I did this conversion on a couple of cars, my 82 TA, my 87 iroc, a 92 GTA and some other cars.

In fact this is so simple, I was stupified. For my 87 iroc I initially fabbed a relay box but the relays are a lot more clunky in operation, this is a lot easier, uses factory stuff and is bullet proof.

 

Here's a simple schematic:



It's from a C3 corvete, same turn signal switch.

C144 is the white one you have to run the brake switch into, just like in that pic. On the divorced brake turn light setups, this wire from the stop light switch is run directly to the brake lights. Run it through the turn signal switch to get that nice dual action going.

 

BTW, the reason I found out was, here in the EU in some countries it's mandatory to have amber blinkers, so a lot of cars have the white wire snipped and the brake signal run directly into the lamps, sometimes converting the back up lights or outside lenses to turn signals. I always undo this because I feel it looks better (US cars should have red indicators,..period) and no one ever seems to get in trouble over it. Undoing this EU mod is the same as turning a factory divorced setup into a non divorced one.

 

As far as I understand I have to connect the blue wire that comes out of the brake switch to the white wire that comes out of the long flat black connector (you name this harmonica, right?).
What still confuses me is the fact that you say I have to insert a new pin, because I already have the white wire coming out of the connector on pin P (see picture attached). So is it then correct that i just have to connect this white wire to the light blue wire coming out of the brake switch.

I'm also asking me, where this white wire that's coming out of the long flat black connector on P goes to? Is it a dead wire that goes nowhere because I have the EU-light-setup?

Thanks again for your help here, it's great!

 

The white wire is on the column side, there is no wire on the wiring harness side. Yes, the long black connector. You have to connect the side from the brake switch that runs to the lamps, not the side that runs to the pedal switch. That indeed is all you have to do under the dash. Then on the rear you wire all bulbs to the turn signal wires (different colors left and right!!!)

 

Alright, I will try it as soon as possible. Thank you, I hope I'll get it.

 

Hello guys, it's done, finally! I've combined the white wire with the light blue. Behind Iused the yellow at the left side and the green at the right side for the blue wire. Thank you, it was so easy. Thank you twinturbo!


I will send a video lazer, it looks amazing

 

Good to hear you got it done.

 

Here:


I've black smoked the Tail light, so on daylight, it's just black. But if I light them up, they are good visible.

 

Does anyone know why the replacement tail and brake light sockets you buy at Oreilles or Auto Zone don't seem to fit?

 

cheap repros, might have to file the tabs a bit or the housings.

 

Looks perfect. I'll do something similar shortly with my new taillight lenses on the Camaro

It seems this is the same conversion as on the 4th Gen Camaros when converting the late 4th gen to earlier tails