My turn signals don't work, and there are some very interesting and perplexing symptoms that will be outlined below along with some info on how the system is setup.

All exterior lights are LEDs. The taillights are all wired together, so I have each side acting as one.

Flashers are electronic, both hazard and signal, designed for LED bulbs.

Headlights - Sylvania Silverstar Ultra 9003 Low/High
Front Signals - LED - 1157 Low/High
Front Markers - LED - Single Filament
Gauge, Console, & Indicators - LED - Single Filament
Rear Markers - LED - Single Filament
Taillights - LED - 1157 Low/High

The following bulbs light under these settings:
***IGN ON***
***Parking Lights ON***

Front Signals LOW
Front Markers
Dash and Gauge Lights
Both Arrow Indicators
Rear Markers
Taillights LOW

***Headlights ON***

Same + Headlights

Signal switch, when switched to one side or the other, makes the arrow indicators that are already on...BRIGHTER...so long as it's switched to that side. All hazards work properly, with the front signals and the side markers alternating while blinking, but only when the IGN is on and the headlight switch is activated.

The following bulbs light under these settings:
***IGN OFF***
***Parking Lights ON***

Front Signals LOW
Front Markers
Dash & Gauge Lights
Both Arrow Indicators
Rear Markers
Taillights LOW

***Headlights ON***

Same + Headlights

The hazards all work, BUT, the blink of the front signals and the markers are as one, and not alternating, like if the IGN and headlights are on. When either the IGN is off, or the headlights or park lights are off, the front signals and side markers blink as one. The only time they alternate is when BOTH the IGN is ON and the headlight switch is at least in the Parking lights position.

I have checked the front marker bulbs for cross contacting, and I have even tried flipping the bulb in the socket. Same for rear marker lights.

I have made sure that the parking light switch illuminates the LOW filament on both the front signals and the taillights, and that the brake switch illuminates the HIGH filament. The hazards blink the HIGH filaments as well.

However, with the IGN ON, and the parking lights and headlights OFF, the signal switch will only illuminate the front signals LOW, the front markers, but NOT THE REAR BULBS IN ANY WAY.

I think I have this explained to the best of my knowledge.

 

Hey Matt,
Did you do a logic diagram on this? If not I can do one for you tonight, scan it at work, and send it to you tomorrow. If you did, if you email it to me, I'll go over it tonight. Let me know.
chuck

 

I am not even sure what a logic diagram is...if you won't mind doing one that would be fantastic.

So what is a logic diagram?

 

have you never seen the box diagrams in trouble shooting manuals, a box with a question and then several "paths" depending on answers (like yes, no)....and so on.

Like this

 

Its a ladder diagram where each rung of the ladder is another function. The outside rails in our case would be battery (+/-). Headlights, breaklights, flashers etc would be another rung. Its a good tool in trouble shooting because it lets you see what you have and what you missed and after this button is pushed this happens. I'll do it for you tonight.

 

Oh yeah I have seen those...I guess I always just called the trouble shooting charts. Cool, I would love to have one of those.

Like I was saying in my other thread I am tempted to cut the whole rear harness out after it exits the body, and test and re-construct the whole harness to the sockets. I did this once, but I may have covered a pre-existing problem which is making it hard to find now.

 

DB,
How much of the original wiring has been changed? Just at the bulb/lights?

Any changes to the switch and its wiring and where those route from original?

When you say your gauge and dash lights are LEDs, did you find LEDs that pluged into the same sockets/locations using the printed circuit board/plastic? Or did you rework/replace the circuit board?

Just trying to gather more "baseline" details of the mods.

 

The only changes to the factory wiring harness in regards to the lights and signals is just at the front and back. I replaced the rear sockets and a few feet of wiring, and the front has had some work by me but I retained the use of the stock front signal plugs.

The switch is unchanged to the best of my knowledge.

I installed LED bulbs directly where the stock incandescent bulbs were with NO other modifications. The gauges, including the speedo and tach, all use factory original circuits.

 

Am assumng you've left some wire slack at the new connections so if you had to cut and the re-solder it would not be too difficult.

Me thinks that you are going to have to follow the "remove all then incrementally add" to find the culprit. The turn signal arrows are probably getting feedback voltage from one of the new sockets.

In software trouble shooting, the first thing we try to find is what was changed last. In this case, it appears that several things were injected at the same time making them all suspect until confirmed good.

 

Hey Matt, I've got a hunch the way the front marker lights are hooked up, which is like the originals may be causing the problem. try just removing the front marker bulbs and see how every thing else works. May be a back feed up into the arrows in the dash as they are on the same circuit.

 

Thanks. I actually tried that. I removed the marker light bulbs from the sockets with no change to anything else.

Next I will try and remove the rear markers and see if that changes anything.

 

Matt, have you tried unplugging the rear harness, there should be a connector near the fuse box. It's a strange problem, kind of a mind bender and I've only been thinking about it for a little while. These cars are too simple to have complex problems. I'm used to working on machines that have hundreds of wires, several electronic controls and satellite communication. I hope you post the solution so I can sleep later.

What happens when you hit the brake pedal?

 

The brake lights come on.

Nothing differs. See, the hazards work no matter what. They flash even when the headlights are on and the brake is being pressed.

However, they do NOT flash, or even come on, when I have the IGN on and the signal switched to one side. The fronts come on, but not the backs.

 

Okay, I found the source of the indicators. I pulled both the front marker sockets, and pulled each bulb. The green indicators are no longer on. I plugged each one back in, and on each side, the indicator lit up per side. If both bulbs are out, both indicators are out as well.

Here's the kicker. I took out the LED bulbs, and tried a stock incandescent bulb that I took out. The filament barely lights at all. I can plug in the bulb...I tried two bulbs, and it takes a few seconds, but it starts to barely turn orange.

Both sockets are the same...the bulbs won't fully light. The LEDs light up but they take a lot less power, and now I have to figure out why the sockets have no power.

What is the path of the wiring for those front marker sockets? I need to try and follow the wires to see if there is a break or short.

The signals still did not work even when the marker bulbs were unplugged, and I still can't get the rear signals to come on when I activate the switch. The front signals will light when I activate the switch, but not the rears.

On and on we go.

 

Corroded grounds?

 

Well my AIM is MIA, so I don't have access to any wiring diagrams.

Where are the ground/s for the front harness? There is a single ground wire that I found that's bolted in near the horn mounts. It's connected fine.

Now, the side marker wiring is as such.

Driver's Side - Light Blue / Brown
Passenger Side - Dark Blue / Brown

The brown is the parking light circuit so they light just like the low filament of the signals, as well as the rear markers and taillights. The blue wires would be the signal wires, which I would assume means the parking light brown wire becomes the ground when the signals are switched on.

I would guess, the blue wires for both sides just tie right into the signal circuit on each side, and I have never messed with or touched the front harness. It's all the way it was when I bought it.

 

Check this link and have him send you a wiring diagram package;

http://forums.corvetteforum.com/show....php?t=1949920

I'll check my diagrams and get back to you.

Check these locations;

drivers side hinge pillar above courtesy light
drivers side bottom of rear crossmember
alternator
front of drivers side fender front skirt

 

If the rear harness has a problem, say with the signal wires, would that translate into a ground problem for the front park lights, which use the signal wiring as the ground when the signals are not being used?

 

Yes, it is my understanding that if you have a corroded/weak ground, the system will back feed through a different available ground and give you your stated problem, provided that alternate ground source is within the same circuit. The ground points just stated are common to the parklights, turn signals and hazard lights.

 

Of the ground points you have listed I have checked the alternator and rear cross member.

The reason I suspect the problem might be in the rear is because the turn signal switch will not make the rear signals do anything at all. With the key in IGN, and the turn signal switch set to either side, neither of the signal lights will light up. However, the fronts do light. They just stay on. The rears won't light at all...which leads me to believe it's a rear signal problem which might also be the bad ground for the front markers.