Another "My Blinker Isn't Working" Thread

[bostonbronconut]

I've been struggling with this issue for years and small fixes have worked temporarily, but I wanted to check with the sages before I take the next step.

My front left blinker is not flashing. It will illuminate when the lights are on, but it will not blink when the hazards are on, nor when I use the turn signal. The right blinker works fine.

I've been using Gemini for s#!ts and giggles and it has been pretty handy outside of some small minor mistakes (using GMC wiring colors instead of Ford). Here is where I am at:

- The ground wires have been cleaned and I've used new metal screws.
- I've replaced the bulb and cleaned the socket out.
- I've cleaned out the crescent plug, and the harness in the steering column is only a few years old.
- The two relay switches have been tested and work; they are also relatively new.
- The voltage to the relay switches is 11.6.
- The voltage to the blue wire in the crescent plug is ~6 volts.

Gemini recommends splicing the power wire from the relay ( 11.6v) to the blue crescent wire (5.8v). It makes sense in theory. It thinks that the wiring is going bad and that is causing the issue. What do you guys think?

As always, thank you for your help on this matter. I'm getting a little sick of using hand signals for turning left.

 

[Oldtimer]

What year Bronco, and stock harness?
Explain relays (or do you mean blinkers), since stock Bronco only has a starter relay, and maybe horn relay in later years.

 

[bostonbronconut]

1977 - stock fuse harness. I meant blinker flasher like the one attached below.

 

[Slowleak]

I would not splice any wires. If the right turn signal works then you are getting power from the flasher unit to the turn signal switch. They use the same power source and wire to the switch. That wire is fine. Also, the hazards use a different wire to the switch. Since the hazard does not work either, it is not the blue wire from the turn signal flasher unit to the switch causing the issue. I expect it is a bad switch or a bad wire from the switch to the bulb.
I would test the wiring from the turn signal crescent connector to the left hand turn signal bulb. That should be a green/white wire.
Does the indicator light in the gauge cluster come on when you use the left turn signal? That would indicate that the switch is working.
I assume you are using standard incandescent bulbs?

 

[Broncobowsher]

The fact you have a working blinker and hazards on one side shows the flashers are both working.
When you say the left side won't flash, are we talking just the front, or front and rear?
How does the left brake light work? As in step on the brakes and cycle the turn signal lever through all 3 positions.
What about brakes and hazards at the same time?

I'm going with a bad turn signal switch. It is a common failure point on any old Ford. But I won't call it until further checks (above, maybe more) have been done.

 

[DirtDonk]

Explain relays (or do you mean blinkers), since stock Bronco only has a starter relay, and maybe horn relay in later years.

Actually, “winker relay“ was a common term to refer to the flasher units.
Relay is not far off of what they do and relay was often used back in the old times. That was how I first learned to call them in the 60s.
I’m not sure where it came from, if it was from books, engineering texts, or local colloquialisms, and therefore something that only people from certain areas would have used.
But it was certainly a thing.
And since the old mechanical ones, actually are an open and close set of points/contacts, I don’t think it’s far-fetched to call it a relay.
Just one that’s “self-resetting“ rather than requires you hitting a switch every time.

Unless there is a very narrow definition of the word relay that precludes using it in this instance?

 

[bostonbronconut]

I would not splice any wires. If the right turn signal works then you are getting power from the flasher unit to the turn signal switch. They use the same power source and wire to the switch. That wire is fine. Also, the hazards use a different wire to the switch. Since the hazard does not work either, it is not the blue wire from the turn signal flasher unit to the switch causing the issue. I expect it is a bad switch or a bad wire from the switch to the bulb.
I would test the wiring from the turn signal crescent connector to the left hand turn signal bulb. That should be a green/white wire.
Does the indicator light in the gauge cluster come on when you use the left turn signal? That would indicate that the switch is working.
I assume you are using standard incandescent bulbs?

The indicator light on the gauge illuminates but doesn't flash.

I used my multimeter on the green-white wire and I get 5.8 volts as indicated previously.

I have installed a new bulb, and it is a standard incandescent bulb.

 

[Slowleak]

I just tested my flasher unit. I have 12.06 volts going in and 6.5 volts coming out. The hazard flasher has 12.06 on both sides.
You said the left front light is on when the lights are on but do you ever see the turn signal light come on? They are on different circuits.
I would start testing at the front and work back to the switch.
Take the flasher out and put a jumper wire in the connector so that you have full voltage going to the switch. With the lights off, turn on the left turn signal and see if the bulb lights up. If not, check the voltage in the socket. If you have voltage, do the same with the right side, since it works, and compare the voltage. If it is the same, then you have a bad ground. If there is no voltage on the left it’s likely a bad wire or connection back to the switch.

 

[bostonbronconut]

Re: Lights - Yes, when the lights are on, the front left blinker illuminates.

I put a jumper wire between the two connectors, and the front-left blinker (driver side) doesn't illuminate, but the back-left one does. This is the same thing that happens when I use the flasher.

I took a look at the ground wires again, and the ground to my driver's side headlight was so worn that it snapped off the pigtail when I was looking at them . The blinker ground wire and pigtail seem fine, though. The headlight ground shouldn't affect the driver's side blinker, right? I am grasping at straws at this point.

Last thing, since we're on this topic, there are two random wires with female connectors (purple arrow) on them and I have no idea what those are for but they are part of the cluster of wires for the driver's side lights.

 

[DirtDonk]

Looks like Horn wires to me. Right location as well. Not sure if all 77 Broncos had dual horn wiring in place, whether they got the dual horns or not. But in 77 you could’ve gone either way with the option sheet.
Verify the colors and will know for sure. Yellow is probably with a green or a blue stripe perhaps?

 

[DirtDonk]

And just checking, since we’re talking about grounds, but do you have good body grounds?
Battery should have the main cable to the engine of course, but then there should be at least one to the body of at least 10ga.
More is better however. And I’ve seen rust and deterioration take it’s toll on the front grill and core support grounding aspects.
In my opinion, it never hurts to add grounding jumpers between the adjacent body panels of the fender, to the radiator core support.
And yes, even though it’s one piece of metal, you can have situations where one headlight is brighter than the other, or one turn signal works, and the other doesn’t. All due to poor grounding.

Glad you found the one broken ground, but maybe you can test this theory by adding a temporary (or permanent) jumper wire between the battery and a good clean surface of the core support.
Preferably near the blinker that’s not working.

 

[Slowleak]

Re: Lights - Yes, when the lights are on, the front left blinker illuminates.

I put a jumper wire between the two connectors, and the front-left blinker (driver side) doesn't illuminate, but the back-left one does. This is the same thing that happens when I use the flasher.

I took a look at the ground wires again, and the ground to my driver's side headlight was so worn that it snapped off the pigtail when I was looking at them . The blinker ground wire and pigtail seem fine, though. The headlight ground shouldn't affect the driver's side blinker, right? I am grasping at straws at this point.

Last thing, since we're on this topic, there are two random wires with female connectors (purple arrow) on them and I have no idea what those are for but they are part of the cluster of wires for the driver's side lights.



View attachment 963781

I agree with Dirtdonk. Those look like horn wires. My 77 has a single yellow wire going to it.
The headlight ground will not affect the turn signal.
There are three wires going into the turn signal/parking lamp housing.
Black is the ground and you said you cleaned it.
Brown wire is for the parking lamp and it works so the brown wire and ground are good.
Green wire is the turn signal and I don’t see where you have tested it for power.
With the jumper in place, and the left turn signal on, unplug the connector where the lamp housing pigtail connects to the harness, I can see it in the photo, and test the green wire for voltage. If you have no voltage then the green/white wire back to the turn signal switch is broken, or has a bad connection.

 

[Oldtimer]

Blinker flasher units are on/off switches, 12v in, 12v out. If you are reading 5.8v out, the contacts must be really bad. Replace it. If it is new, replace the connector it is plugged into.

Remove lenses from front turn signals, so you can see the individual filaments in the bulbs.
Is the dim filament only illuminating when parking lights are on?
Is the bright filament only illuminating when turn signal activated?

Grounds:
Is shell of bulb making good contact with socket walls in fixture?
Is ground wire making good contact with fixture?
Does ground wire have continuity from fixture to lug (ohm meter)?
Is lug clean and shiny?
Is lug bolted to clean and shiny surface on core support?
Does core support make intimate electrical contact with inner fender skirt? (60 years of rust and vibration do not help)
Does inner fender skirt make intimate electrical contact with inner fender?
Is there a good ground wire running from battery to inner fender?
The battery ground wire to engine block does not count, unless the middle of it is bolted to inner fender.

I think the red circle is the harness connector for fixture in question?
Unplug it and check for turn signal and parking light function at the main harness connector.

 

[DirtDonk]

Researching it a little more, I think my early use of the term “winker relay“ was stemming from Honda motorcycles.
Apparently the Japanese made the term common in the 50s and 60s. And that’s probably the shop manuals that I got it from. I thought it was from GM, but more than likely it was from Honda.
Or the motorcycle magazines, I was reading starting in the late 60s.

 

[SLOWnEASY]

You should be able to just swap the turn signal and hazard flashers with each other and see if the problem moves as well.

 

[DirtDonk]

It really should not be the flasher unit itself.
Shouldn’t be, but doesn’t mean it can’t be.

But since the right turn signals work, the flasher is working. The fact that only one side isn’t working, means that everything up to the flasher, and then up to the turn signal switch, is functioning.

 

[SLOWnEASY]

Thanks DirtDonk for trying to be diplomatic but yeah I missed the point on this one with the flasher unit suggestion. If it flashes for right turn it's going to be fine for left turn as well.

 

[pcf_mark]

Super low tech test - when you put the turn signal into the place that it lights but does not blink gently apply pressure and move it up and down slightly. If it starts to blink it is in your signal switch.

 

[bostonbronconut]

Super low tech test - when you put the turn signal into the place that it lights but does not blink gently apply pressure and move it up and down slightly. If it starts to blink it is in your signal switch.

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.

 

[bostonbronconut]

Blinker flasher units are on/off switches, 12v in, 12v out. If you are reading 5.8v out, the contacts must be really bad. Replace it. If it is new, replace the connector it is plugged into.

Remove lenses from front turn signals, so you can see the individual filaments in the bulbs.
Is the dim filament only illuminating when parking lights are on?
Is the bright filament only illuminating when turn signal activated?

Grounds:
Is shell of bulb making good contact with socket walls in fixture?
Is ground wire making good contact with fixture?
Does ground wire have continuity from fixture to lug (ohm meter)?
Is lug clean and shiny?
Is lug bolted to clean and shiny surface on core support?
Does core support make intimate electrical contact with inner fender skirt? (60 years of rust and vibration do not help)
Does inner fender skirt make intimate electrical contact with inner fender?
Is there a good ground wire running from battery to inner fender?
The battery ground wire to engine block does not count, unless the middle of it is bolted to inner fender.

I think the red circle is the harness connector for fixture in question?
Unplug it and check for turn signal and parking light function at the main harness connector.
View attachment 963782

I'll installed a brand new bulb and I've cleaned out the socket before putting it in. As I mentioned before, when the running lights are on, the bulb works, but it won't flash.

The lug to the front wall has been cleaned and sanded multiple times, including the O-ring on the wire.

I have two grounds on the battery: one to the engine and one to the side wall.

As some of the guys on this forum knows, I'm a bit of a newbie when it comes to tech talk. What exactly did you want me to test with the harness connector?