Tail light wiring

Are the side marker lights LEDs? If they are, that could be the cause.

Let me know.

Joe

That doesn't even make sense. Did you install the 194s? Are you certain they are LEDs? If they go dim with an LED flasher, that makes sense if they aren't LED's. When you disconnect, are you removing the bulbs or disconnecting the lights from the harness?

Joe

Check the ground for the marker lights to see if there is excessive resistance. Something is causing them to dim.

Okay, you will have two wires showing power, but it still grounds through the front park/signal lamp.

Take a look below. I highlighted the things to identify them. Ground goes from those marker lights to the front park/signal lights and then to ground on the left rad support bracket.

I have a very strong feeling either one or two things are happening. Either the ground at the rad support is weak and fails under the extra load, or the splices are bad.

Just for the heck of it, run a good ground for both front signal/park lights. That will indirectly create a new ground for the side markers. If the same problem happens, then it has to be the splices.

Also, if you want to try this. Remove one of the 194 and see if the system does the same thing. Do it on both sides. If it is a splice problem, it should only happen when one of the bulbs is plugged in. In other words, if the left side is the problem, the right side and all lights should work normally when the left bulb is out. That will reduce the load on that splice.

Let me know. I know this may sound crazy, but wiring in and of itself can drive anyone crazy. Hang in there. You are doing a great job.

Joe

Hi,

If you run two new grounds, will they both work?

Let me know.

Joe

Ugh! LOL Once again, that makes no sense. Okay, check for power to both of the power supplies when each of the two circuits is actuated. If we have power, it doesn't leave much, a socket or bad LED.

I have to be honest, I love a challenge, but this one just doesn't make sense.

Stupid question. If you have all the LED installed and remove the resister relay and replace it with the original one, what happens? I realize flashers will hyper flash, but do all lights work?

Hi,

As you're already aware, this makes no sense. LOL The absolute only thing I can think of is if when everything is connected (even though they are LEDs) there is enough of a power draw to cause failure at a connection. Keep in mind, when you have a

I have one more thing to check before I ask the site owner for his opinion. Connect everything so that the lights go dim when turned on. Check voltage at the marker lights. Realize that LED flasher is going to drop voltage, I want you to check it when everything is connected and then when one of the marker lights is disconnected and all others are working normally. I just want to see if there is a power drop.

Let me know.

Take care,

Joe

Sounds good. Let me know what you find. Also, I am going to ask Ken for his thoughts. He is excellent with these types of issues.

Take care,

Joe

Ugh! Then what could be causing them to dim? Okay, let's look at this from a different point of view. We have focused on the marker light causing the issue. If voltage doesn't change, there has to be an increase in resistance to a ground. I don't want to ask this because you likely already told me, but have you checked grounds for the signals and parking lights as well?

Also, keep in mind that the ground wire may be in good condition, making good contact, but the ground source may be in poor condition. I don't know where you are or if rust is an issue, so I thought I would mention that idea.

Joe