Further troubleshooting perplexes me. My problems are worse than I thought.

Not only are my turn signals gone, so are my backup lights. I have brake lights, unless I turn on the headlights. Then I only get a left brake light. I do get two tail lights with the headlights on, but the right side goes out if I step on the brake.

This morning I had all working lights and signals. The only electric wire I touched all day was to reconnect an old grey corroded power wire to the light bulb behind the center console for the wiper switch.j Illuminates with headlights.

How did so much go wrong from pulling the turn signal flasher unit and putting it right back on? How did the electric gremlins get loose? I didn't monkey or yank on anything that would cause it, as far as I know.... Could connecting the wiper control dash light have caused a bad ground??? I'm so confused.

I appeal for help.

 

Start with a new 20 amp fuse at DIR SIG Back up

 

Every fuse in the panel looks visually great. Just to be sure, I did switch out the DIR SIG Back Up fuse. No change in lights.
I continuity tested the 20A fuse that I took out. It was good.

I crawled under the rear bumper cover and thought I might have found something... saw the right outside tail light had a loose wire--a black wire with a spade connector and rubber sleeve that goes into the round hole of the back of the light bulb plug (based on the opposite side light plug). I verified the bulbs on both outside tail lights still had intact filaments. Then I plugged the black wire into the round socket of the right tail light, and it went right in. It didn't fix anything. It got worse. Now I have no brake lights, headlights on or off. I know I had them an hour ago before my last post. I am being punished for something.

So now I have no brake lights at all, no turn signals at all, no back up lights at all, and only the left tail light when headlights are on. Everything looks good at the fuse box. This is so bizarre and unexpected. I don't know what to try next. Totally baffled. Killin' my mojo.

As for 4-way flashers, I don't know if they work. The button on my steering column feels mushy and worn out. It doesn't seem to push in or pull out. I've never tried the 4-ways before, but I do know that I've had working back up lights, tail lights, brake lights, and turn signals. I can't fathom WTH I did to kill all that!

 

Try connecting a temporary ground wire directly to the bulb of each tail light. Then, start testing further,

For the signals, check that there is power at the flasher plug.

 

Thanks for the suggestion, Lionel. I will pick up new bulbs at lunch and try this when I get home from work. I am very grateful for your assistance in working this out, and will post any progress or change. I am indebted to this community and look forward to when I can help someone.
Chip

 

If one connection was corroded, there are probably more. Even on my 04 C5, some of the ground connectors were corroded enough that I had to clean them. When you replaced your flasher you either moved some other iffy connectors or blew out the capacitor.Best thing to do is to systematically start chasing down the gremlins like suggested above. Even my C5 had some corrosion issues and it was a garage queen.

 

Thanks Stonebreaker. I think I'll also get a replacement harness flasher connector to replace the one that held the very badly corroded spade contacts. I couldn't figure out how to clean inside that bit. Hey, other than for NCRA points, doesn't the capacitor on the turn signal flasher just suppress AM radio noise? Shouldn't I be able to run a turn signal flasher without the capacitor? It would be one less piece to the puzzle...

The flasher unit wasn't hard to remove and the location didn't require any pulling of wires. Just untucked it and out the harness came. Unplugging / plugging also was effortless. Sooner or later will work this out, SO grateful for help suggestions.
CHip


Chip

 

Here's how:
Run a wire to a good ground and touch the other end to the BRASS pars of the bulb socket.


For the signals, check that there is power at the flasher plug.

Also, with the fuse installed check for 12 volts on both sides.

 

DUB

 

FOR WHAT THIS IS WORTH>

Due to you removing the capacitor from the turn signal flasher connector the new turn signal flasher may not grip as well due to the terminal in the connector was stretched out for the added thickness of the metal terminals on the capacitor. So you can be not making good contact and get a good grip.

The PINK wire that is in your turn signal connector is the power coming from the fuse and you want to make sure that when the key is ON you have battery voltage at this terminal. IF you don't...regardless if you installed good new fuse...you can have dirty contacts in your fuse panel that holds the fuse and it needs to be removed and cleaned so your BATTERY VOLTAGE at the INNER terminal that holds your fuse. In the photo below. Power comes in at the outer fuse terminal with the yellow arrow and passes through the fuse and go to the inner terminal with the red arrow. So actually touch the inner terminal with your volt meter to check it. IF you have a bad connection where the fuse is being held it can show a voltage drop.




NOW...the PURPLE wire in your turn signal flasher connect is the PURPLE wire that is gong to your turn signal switch connector. and you want to make sure you are getting battery voltage at THAT connection.

Now the same holds true for your brake lights in regards to a bad fuse connection The key does not need to be turned on to check.

The battery voltage comes in on the BRAKE FUSE on the outer terminal with the white arrow and goes to the inner terminal with the blue arrow.


The POWER goes to your brake light switch mounted by your brake pedal and the ORANGE wire in it is where the battery voltage is coming from your fuse. Then the WHITE wire in the brake switch connector is going to the WHITE wire in your turn signal switch connector.

Keep in mind you have a rear body wiring harness connecter connected right above your left kick plate area and THAT can also be dirty or corroded.

The YELLOW and DARK GRREN wires coming out of your turn signal connector are for your bake lights and rear turn signal lights. SO...if you press your brake pedal you should have battery voltage that the YELLOW and DARK GREEN wires at your turn signal connector under your steering column.

The other issue is more than likely a ground problem. Because you can get your running lights to work...adn your and get your turn signals to work separately. BUT if you have your running lights ON and try your turn signals and they do not work. It is a ground problem. at THAT bulb that is not working.

DUB

 

DUB, thanks for your time on this. The copper spade on the capacitor is really thin. It's entirely possible that my flasher socket is still full of corrosion inside. That might explain why I didnt' get turn signals back when I put the original working flasher unit back in (along with the cleaned capacitor). I'm currently discovering the fun of trying to find a local parts store with a replacement 2-wire flasher socket connector in stock. Scarce as hens teeth, so I ordered one from Amazon . I will install if I don't get good 12V at the turn signal flasher socket.

And Man, oh, man... thanks SO MUCH for this color coded troubleshooting guide that follows:

This is SO handy to have. I had no idea I could check brake light connection at the fuse box with the switch off. Good to know.

That gets my attention, Dub. What does the rear body harness connector look like? I have some floppy wires hanging loose that were interfering with my hand getting to the fuse box when I went to change the flasher/back up light fuse (as suggested by Peterbilt). There is a brown wire connected to a small black box (maybe 1" x 1.5" x 1/4") that was lying loose and in the way. Perhaps one of the loose rat-nesty wires I had to move out of the way to get to the fuse panel was the rear body wiring harness connection. Can you help me identify the rear harness connector?

This information is incredibly helpful, Dub. Can't thank you enough. Looks like I'll be spending quality time with the volt meter while wedged headlong into the drivers side foot well, looking like Free ***** trying to swim through a sewer grate... That small space and my large size combine to make for an interesting engagement...

I have bought fresh bulbs for all the problematic lights, and will use the methods you and others shared showing how to test the ground at the bulb locations. Again THANK YOU for this very clear information about how to go through troubleshooting. Now I have a game plan and can go back to working on the car with logic and reason instead of random parts swapping. I look forward to taking the steps here and working this mess out. Having a decision tree style game plan makes all the difference in the world and beats back the frustration factor that was killing my sweet C3 karma.

You guys are so kind to help me like this. Much gratitude, y'all... I will post results after I go bond with the C3 tonight.
-Chip

 

Peterbuilt, that picture you shared is worth 1,000 very very good words. Thank you for clearing up a question I had in my head, but had not asked yet. Thank you sir.

Roger that, Peterbuilt. I suspect the flasher socket still has corrosion inside that I can't clean. I have ordered a replacement flasher socket to install if that turns out to be the case.
If the turn signals and the backup lights share the same circuit, it would make sense that I lost backup lights if I failed to make a good connection back at the flasher plug upon reassembly (due to corrosion in the socket).

Yep. Mr. Dub gave me some very clear instructions on how to do that for several of the involved circuits, agreeing with your suggestion. You guys are real princes, I hope someday I can return the favor in kind.

Deep thanks for removing the cloud of confusion and offering up a troubleshooting path. I am so grateful for your time and thoughts. I'll keep the popcorn rolling and post my test results and findings as soon as I get time with the car. Hopefully tonight...

-Chip

 

No, a bad connection at the flasher socket wouldn't cause the backup lights to stop working.

 

FIXED!!!
All lights working as they should!
What was it?
Pretty much *everything* people suggested.
DUB wins the big prize. DUB, you were right about the fit of the blinker in the harness socket. It was loose in there. Shimmed with copper blade. Blinkers work now.
DUB's guide gave me confidence to work through the fuse panel. Found some corroded fuse holders. Verified voltage was all good at the panel.
Backup lights work fine now... one bulb was black... I bet when the wife checked backup lights for me the day of the sale she only saw one but thought she saw two.
Brake lights work now.
Tail lights work now, both with headlights on and off. I found a bad ground wire in the right tail light bayonet. I couldn't replace the broken spade connection, but I did find a replacement bayonet which I spliced in.

Dub, Peterbuilt, and Stonebreaker... I owe you guys an adult beverage of your choice. I can't thank you enough. Y'all are the good stuff. Thank you, thank you, thank you. You gave me a map I could follow, and my sweet C3 karma is back and healthy! You guys ROCK!

 

Glad it's fixed!
Lionelhutz is also very helpful with electrical problems, he deserves a thanks too.

 

Awesome! That's what makes car guys some of the best guys to hang out with. Before I got into vettes, I had a 96 impala ss to haul around my family (it was either that or a mini van <shudder>). I made friends in that club that I still hang out with to this day. I ran 11's in that car and it was my daily driver. I'm still stuck in the low 13's for my vettes, although I'm looking for 11's in this next one.

 

 

SUPER GLAD that you got this fixed and I had NO DOUBT that you would due to his electrical circuit is so basic and generally easy to find the problem and get it working again.

To answer what your rear body wiring connector looks like it will be w wide black connector that as two rows on it and about half the size of a normal harmonica..

If you do not have one..it is wise to obtain a GOOD wiring diagram for your car form a reliable source such as one of the Corvette venders. Give Willcox Corvette a call on that. Some of these laminated wiring diagrams are colored so tracing the circuits is easier and would be some of the best money you spent on your car.

And my hats goes off to 'Peterbuilt' for posting a good photo of the fuse panel that I used that aided me in helping you.

ON ANTHER NOTE:

This is not directly related but can be helpful.

KNOWING that the power is coming in the fuse panel on the outer terminals one each side.

The CENTER terminals in the photo in this thread would tell you the EACH one of these terminals is being protected by the fuse that is supplying power to it.

So the BAT terminal is protected by the CLK LTR /CTSY fuse and it is HOT all the time. So if the fuse blows...so does the power to the BAT terminal.

The ACC and IGN terminals are the exact same way that they are protected by the fuses to the right due to working ONLY when the key is turned on.

SO..When ever a person uses these terminals ...keep in mind that they are protected and IF you are plugging in component that draws a lot of amps and is more than the actual fuse beside it can handle WHEN that factory component is also being used. The fuse can blow.

YES...The IGN terminal sir being protected by the "DIR SIG/BACK UP 'fuse. Which is not used always ON. But it is being protected by a 20 amp fuse. So plugging in something that is drawing 15 AMPS...for example....a person would need to be careful if they put in a 30 amp fuse. Because now ...even though the fuse may not blow,. the wire you attached to the IGN terminal is more than likely so small in gauge size that the fuse is not protecting THAT Wire nor the wires to your direction signal any longer correctly.

You all would be shocked in the wiring nightmares I come across and how the car has not set itself on fire...even though what was installed works.

CAUTION should be used IF a person is going to increase the amp rating of that specific fuse due to it blowing BECASUE you need to know the wire gauge size so you do not but too large of amp rated fuse in there and burn up your wiring. Because a fuse is not there to protect what it is powering up. A fuse is there to protect the WIRE from burning up.

DUB

 

Thank you. The combined information you and the others shared made this a very do-able task. Good project management is invaluable.

OK, great. I saw it just above the fuse panel, once I got my head far enough in the foot well. Thank you.

Just got Eckler's 1976 AIM. I'll check Wilcox too. Laminated is good for me. Appreciate the tip!

You guys make a helluva team. I salute your knowledge and willingness to share.

Dub, I hope you don't mind if I've been printing your instructions and keeping them in my 3 ring binder of Corvette diagrams and documentation.
I *really* appreciate the time and effort. I promise I'm soaking it all in. Good stuff. Your gift of time and knowledge has not been wasted on me, and I hope it will help others.

Thanks for showing me how to logically approach electrical system issues with this generation of cars, all of you...

Chip in Cary NC