ok im having a little wiring issue. ive looked at the wiring diagrams and ive tried my best to make it work but i cant seem to get it right and i was hoping someone could help to point me in the right direction. when i turn on my lights the tail lights come on to full brightness. this is an issue because when i press the breaks there is no visible difference, also when i turn on the right turn signal everything works ok but when i turn on the left one they both blink, the right one is a little dimmer. if someone could help me out i would greatly appriciate it. thanks

 

Did you remove disconnect any plugs and reconnect? If this is something that just happened look at the ground connections in the back, near the tail lights..

 

Did you do somthing to your car that might have caused this change, or did the car start doing this on it's own?

And what year is your car?

 

sorry, its a 65. i bought the car like this and did some work on it and was able to make it a little better but i cant get all of the problems to go away. it was hard to tell where the grounds go off the tail lights. if anyone has some pictures or somthing i would be great . electrical kind of isnt my thing if you cant tell already.

 

Ok, I was going to check in the trunk of my son's 66 but he has the keys, so I am going to throw up a few things and re-post to you when I can get into the trunk. I have lots of experience with GM vehicles, and I think that the same colors are used on mustangs, so at this point I am going to assume, and post some general info.

The Tail/Stop/Turn Signal lights are controled by 3 wires and a common ground. If there has been wiring work done in the trunk I would start here for resolution. The colors I an giving now are GM, the function is the same regardless of color.

If the tail lights have been re-wired with tape connections or butt connectors your problem is probably in the trunk. If the stock harness is intact do not cut it, the problem is probably elsewhere.

OK, I had started a big long message telling you how to troubleshoot this, but I want to get the colors right for you first. I will repost soon.

Have the wires in the trunk to the tail lights been messed with, r is the stock harness intact?

 

they have deifnately been messed with...im pretty confident thats where a lot of the problem is but i cant figure it out. i really appriciate your help. thanks

 

Don't know if you tried it already but Go with easy solution first...replace turn signal relay and hazard emergency relay behind instrument panel...any luck with this? Next check turn signal assembly behind horn...

 

Hello connor, My son just came in I am too tired to go look right now, but I am reasonably sure that the problem can be resolved in the trunk, it will just be a matter of getting 3 wires in the right place. I need to get the colors of the wires to make the process simple. I will re-post in the morning with this info.

I have serious insomnia combined with the time change, but I think I can sleep now, and I better it is almost 2:00 am.

 

Ok, I am doing this for the second time, last time I got it all done and then I could not post it, so this time I will write it elsewhere and paste it in.

Ok first we need to establish that the wires in the trunk are correct. This may not be your problem, but once we are sure that this is right, it will allow us to troubleshoot the rest of the system if we need to.

From your previous posts I am assuming that the wires in the trunk that go to the tail lights have been modified, so we should not have to worry about messing up the stock harness. If this is incorrect let me know.

The first thing I would do is to disconnect the taillights; there will be two wires going into the back of each light assembly, plus a ground wire. Right now we will concern ourselves with the two “hot” wires, for now leave the grounds as they are.

On the left side there should be a green wire and a black wire coming out of the taillight assembly right behind the bulb, on the right side there should be an orange wire and a black wire. Take all 4 wires loose at a splice connection that I am assuming you will find near the taillights. Strip back the insulation on all 8 ends, Make sure that these wires do not cone in contact with each other or any metallic part of the car.

At this point, you will need a test light. Turn on the parking lights only. Using the test light confirm that the black wires coming from the car side of the harness are both “hot” when the parking lights are on and “cold” when the switch is off. Once this is confirmed turn the parking lights back on and using the confirmed “hot” wire, touch the end of the of one of the wires coming from the taillight assembly to this wire. Switch wires until you can confirm which wire is the one that dimly illuminates the tail light and permanently hook this wire to the hot wire that works with your parking light switch.

Do this for each side.

Then you will be left with one wire for each side to hook up. First turn on your left blinker (with the parking lights off) then using your test light confirm that the green wire coming out of the car side of the harness blinks with your blinker, and that the right side does not. If this checks out you can hook up the left side wire to the wire that is left on the left side of the taillight housing. If everything is good, the left signal should be blinking bright now.

Do the same on the right side, except it will be an orange wire instead of a green one . If the blinkers work you should have brake lights as well.
If this does not work, get back with me with your results, and we can further investigate for trouble spots.

 

i only have 2 wirescoming out of each light assembly...i dont see a 3rd ground wire.