Another "My Blinker Isn't Working" Thread

[bostonbronconut]

Quick update: I've replaced the headline pigtail and the headlight functions correctly, but still no luck with the blinker. The wiring on this rig is a rat's nest. I've found another new wire that looks to be cut and goes no where, but I don't think it has anything to do with this issue.

 

[Oldtimer]

Looks like GR/BK stripe wire.
That would be Hi Beam circuit to headlights, or if under dash to Hi beam lamp in cluster.

 

[Oldtimer]

What exactly did you want me to test with the harness connector?

Use a test lamp (HF $5) to determine if you have left turn blink on the GR/W stripe wire.

 

[Slowleak]

I think what you are overlooking here is that the running lights and the turn signal are independent. The fact that the running light works means nothing. The wire for the running light is brown. The turn signal wire is green/white. They use different filaments in the bulb and are completely independent of each other. Ignore the running lights. Don’t even turn them on.
The only way to diagnose this, as has been mentioned several times, is to test for voltage coming from the green/white wire at the left turn signal. You can do it like Oldtimer mentioned, or use a voltmeter. Unplug the connector behind the housing and check voltage from the green/white wire with the turn signal on. Ignore the running lights.

 

[DirtDonk]

I replaced the signal switch not too long ago; unless I damaged it recently, that shouldn't be the issue. But I did try wiggling and moving it to see if that worked and the gauge light and rear brake light turned on but did not flash. The front blinker does not turn on at all.

Ok, you missed one really important point that has come up regularly (FAR too regularly in fact!) that new parts SUCK!
Did I shout loud enough that time? Haha, it's the truth. We can no longer say "it's new, so it should be fine" for any part bought in the last twenty five years. But especially so, for parts bought in the last ten years.
No matter a reputable seller, no matter a reputable manufacturer (or "sourcer of imported parts" just as likely), no matter how good it looks, any new part is under suspicion until it's been proven innocent.

So don't ignore your "hmm, sure sounds like a bad turn signal switch" internal voice, or the voices from out here. Your recently replaced switch is absolutely still a suspect.
Until you've tested it and it turns out to be good.

But the second most common failure point of a new turn signal switch, right behind the switch itself, is the chance of a buggered wire while installing it. No matter how careful, a shaved outer insulation as it passes over a sharp metal edge, is a real thing in the Bronco world.

So, while your issue might still be something else, I just had to call you out on that particular remark.
We say it al the time here: "just because it's new, don't mean it's good" and we mean it!

We even try to keep track of the life time of a particular pat, the manufacturer's name and source purchased from.
Personally I really want to know if any of our switches ever fail. And as quickly as possible, so we can check the rest of our inventory to see if any more are not good.
Unfortunately, with a part that worked for awhile then didn't, we can't really find the faults on the shelf. Only feedback after customers start using them, can help us along.
Whether that means finding a new source, or communicating the issue with the existing source, or just information so we can inform customers, knowing is good.

Good luck. Hopefully it's still something simple. But if it turns out to be the switch, well, as mom used to say... Let that be a lesson to you! Hah!
Good ol' mom...

Paul

 

[Slowleak]

Just to keep this thread going here are the troubleshooting tips from the ‘77 shop manual for one turn signal not working.

First step is to test for power at the bulb socket, that means testing the green wire. No need to test the switch because only one turn signal bulb is not working and the dash indicator light works.

The signal switch is tested by checking if the indicator light in the gauge cluster comes on, and it does.

Both of these tests point to a bad wire to the front left if you find no power there.

 

[bostonbronconut]

I think what you are overlooking here is that the running lights and the turn signal are independent. The fact that the running light works means nothing. The wire for the running light is brown. The turn signal wire is green/white. They use different filaments in the bulb and are completely independent of each other. Ignore the running lights. Don’t even turn them on.
The only way to diagnose this, as has been mentioned several times, is to test for voltage coming from the green/white wire at the left turn signal. You can do it like Oldtimer mentioned, or use a voltmeter. Unplug the connector behind the housing and check voltage from the green/white wire with the turn signal on. Ignore the running lights.

I tested the green/white wire at the crescent plug and the harness/pigtail (or whatever it is called) and my multimeter showed 5.8 volts at both locations. And, just for sh!ts and giggles, I tested the passenger side blinker as well, which works, and got a reading of 5.7 v.

 

[Slowleak]

I tested the green/white wire at the crescent plug and the harness/pigtail (or whatever it is called) and my multimeter showed 5.8 volts at both locations. And, just for sh!ts and giggles, I tested the passenger side blinker as well, which works, and got a reading of 5.7 v.

Was that with the flasher in place or with the jumper in place to replace it?
Try the same test using the hazards rather than the turn signals. See if you get more voltage or the same amount.
It could still be a ground issue or an issue in the bulb socket itself.
A test light like Oldtimer pointed out would let you test by bypassing the bulb, socket, and ground.
You can also use your meter to test for continuity between the connecter inside the socket, and the end of the pigtail wire or check for voltage at the terminal inside the socket. Sometimes these old wires break internally.

 

[bostonbronconut]

Crazy question: Should I swap out the passenger side blinker for the driver's side to see if that works? It could confirm if it is the socket/light itself, right? Or is there another step I should do before?

 

[Slowleak]

Crazy question: Should I swap out the passenger side blinker for the driver's side to see if that works? It could confirm if it is the socket/light itself, right? Or is there another step I should do before?

I was going to suggest that but I would try to test the socket first. Just take out the bulb, turn on the turn signal, and if your multimeter has a probe touch the terminal inside the socket to check for voltage with the other lead on a good ground. You should see the same voltage you saw on the green wire in the pigtail connector.

 

[Slowleak]

I’m not too concerned about the 5.8 volts you see. I see the same on mine. It is hard to accurately test flasher units with a voltmeter since they require resistance from a bulb to function. The voltage fluctuates when you use a voltmeter with a flasher unit. That’s why i asked if the flasher was in place.

 

[bostonbronconut]

Welp, after all of that, I remembered I bought two new park lights a few years ago (Drakes) and never installed them. I figured that it couldn't hurt to just hook up a new one real quick and give it a go, and it blinked like the first day I took my Bronco out.

Thank you for all of your patience and for trying to help me figure this out. Looks like the old blinker was done and I just needed to install a new one. Thanks again for all of your help with this matter. You have no idea how much I appreciate this forum and this community.

 

[Slowleak]

Welp, after all of that, I remembered I bought two new park lights a few years ago (Drakes) and never installed them. I figured that it couldn't hurt to just hook up a new one real quick and give it a go, and it blinked like the first day I took my Bronco out.

Thank you for all of your patience and for trying to help me figure this out. Looks like the old blinker was done and I just needed to install a new one. Thanks again for all of your help with this matter. You have no idea how much I appreciate this forum and this community.

That a good news. Probably a bad wire in the light assembly itself. Glad you got it fixed!

 

[DirtDonk]

So now you have to also verify that the correct filament is working.
Many of them are wired backwards, so make sure that when the parking lights are on, it’s the dim filament and when the signals are flashing, it’s the bright filament.
You may already have noted it, but if you weren’t looking for that, double check.