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Those annoying turn signals

phred

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Why would front ts not work when the headlights are on??


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Glass Pony

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Why would front ts not work when the headlights are on??


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Did this happen all of a sudden or did you not too long ago change something in the turn signal bucket or associated wiring?
I had that issue when I installed new turn signal buckets and the wiring was backwards on them.
 
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phred

phred

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All original 75 ranger. It’s been a problem for several years.


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triracer67

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blinkers

Do the flashers work with headlights on? Maybe this will provide a little more direction?
 

Slowleak

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Sounds like bad grounds. Do they work when only the parking lights are on?

I would clean all the grounds and maybe test with a ground wire direct from the battery to the core support or a bulb ground wire....
 

Nothing Special

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I'll "third" that. I have issues with one of my front turn signals sometimes not working when the headlights are on. In my case wiggling the bulb in the socket is the (short-term) cure.

And to broaden the application, absolutely every time I've had a confusing electrical situation on a vehicle, it's always turned out to be bad grounds.
 
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phred

phred

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Thanks guys.
Grounds were the first place I was gonna start. This truck came in with a bad transmission (actually just 2 qts low on fluid) and as the owner was walking away. Oh and the turn signals don’t work when the headlights are on. Hope to get to it later this afternoon. 🤞


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DirtDonk

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And if the grounds look and feel good, don't stop there.
Follow them along and check the headlight connectors first. Then, and even if you don't think it needs it, I would run a jumper ground wire from the main body tub, or battery directly, straight to the ground wires on the core support.
If not direct to the wires, then at least by creating your own new ground wire to bond the core support to the rest of the system.

In fact, you can even test this theory by simply running a temporary ground wire from the battery negative to the headlight ground.

Oh, and if you have not already (sounds like you haven't) you need to verify that the bulbs are good and the sockets not rusted out.
This is an issue with original Broncos with light problems often as not.

Good luck.

Paul
 
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phred

phred

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I checked all the grounds. I can get a power to the bulbs but they won’t flash. I put in new bulbs and still nothing. Put my test light in the socket and it flashes. I ran temp grounds directly to the battery just to be sure.



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gnpenning

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I have more questions than answers.
You pretty much verified it's a ground problem. Since your test light flashed with a different ground then it should work if you run a wire into the socket and ground it to the battery or where the test light was grounded. I wouldn't mess with it, just buy new sockets. You can touch a ground wire to the ground area on the bulb and a few other versions, in the end you can replace the socket and be confident in the repair.
 
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phred

phred

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Thanks. The sockets are newish. Not the factory ones. Seem pretty flimsy and cheap. Looks like this guys gonna have to pony up for new ones again. Cheap chinesium junk.


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Viperwolf1

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Thanks. The sockets are newish. Not the factory ones. Seem pretty flimsy and cheap. Looks like this guys gonna have to pony up for new ones again. Cheap chinesium junk.


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Before you give up on them try one more thing. Sometimes the new turn buckets have the running and turn wires reversed. That makes the running light so bright and the turn light so dim that you can't see the turn light flashing. Try reversing the wires.
 

Broncobowsher

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Jun 4, 2002
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Sure it is a '75? The early ones the park lights were designed to turn off when the headlights came on. But that changed around '70. It was a leftover from primitive electrical systems where every amp was valuable that running the park lights and headlights might mean that at night there may not be enough generator output to keep up. By the 70's alternators existed and there was plenty of power. Regulations changed and running park lights was standard practice and useful to define the corner of a car where a headlight might be burnt out.
 
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