Rear blinkers not working.

[CaliBronco29]

I have a 72 ford bronco and cannot get my blinkers to work. I have replaced my turn signal switch and my flasher for both the hazards and turn signal. My brakes and hazards still work but not my turn signals. I had a new wiring harness installed in 2015 American automotive.

When measuring the voltage into my turn signal flasher I am getting about 10 volts in and only 4 to 5 volts out. When measuring it starts to click but they won’t turn on. (I think because it is almost grounding it through the multimeter.)

Next I ran a jumper wire across the switch and still the lights wouldn’t work. The voltage was going into the turn signal switch but was not measuring anywhere out of it.

Also my fuses keep popping for breaks hazards and turn if I have the 15 amp fuse in there.

I do have led brake lights and front turn signals with the led flashers.

Any ideas?

 

[DirtDonk]

Can’t give you a direct answer yet. Still trying to wrap my head around it.
But one thing you can do, generally with any of these old rigs is clean the fuses.
There are only five fuses, but the old glass type often build up a layer of oxidation around the contact points. Assuming your fuse panel isn’t super rusty or beat up, you may just want to remove all the fuses, wipe them down, clean the contact points, and then put them all back in.
Since the smallest one is the hardest to get out, and is only for the instrument cluster lighting, you could probably leave that one in if it gives you trouble.
But if you can get them all out and clean them, that’s a good first step.
What made me think of that is the low-voltage reading you got. That’s quite a bit of difference from the 12+ that you should be getting.

Even though the rear turn signals are not working, are the fronts? The indicator lights on the dash are flashing when you use the turn signals?
And a side question. When the hazard flashers are on, and the brake lights, are you sure the filament that is lighting up as the bright one?
What happens when you try all of this with the headlight switch pulled to the first position to turn the running lights on?
That all seems fine and when you hit the brakes, the lights get brighter in the back?
And just another side question. When the hazards are on and you push the brake pedal, do they stop flashing and stay illuminated?
Just a few things to drill down into this problem.

 

[CaliBronco29]

Can’t give you a direct answer yet. Still trying to wrap my head around it.
But one thing you can do, generally with any of these old rigs is clean the fuses.
There are only five fuses, but the old glass type often build up a layer of oxidation around the contact points. Assuming your fuse panel isn’t super rusty or beat up, you may just want to remove all the fuses, wipe them down, clean the contact points, and then put them all back in.
Since the smallest one is the hardest to get out, and is only for the instrument cluster lighting, you could probably leave that one in if it gives you trouble.
But if you can get them all out and clean them, that’s a good first step.
What made me think of that is the low-voltage reading you got. That’s quite a bit of difference from the 12+ that you should be getting.

Even though the rear turn signals are not working, are the fronts? The indicator lights on the dash are flashing when you use the turn signals?
And a side question. When the hazard flashers are on, and the brake lights, are you sure the filament that is lighting up as the bright one?
What happens when you try all of this with the headlight switch pulled to the first position to turn the running lights on?
That all seems fine and when you hit the brakes, the lights get brighter in the back?
And just another side question. When the hazards are on and you push the brake pedal, do they stop flashing and stay illuminated?
Just a few things to drill down into this problem.

The front blinkers do not work either.
The indicators in the dash do not turn on when the blinker is engaged but do for the hazards. When the running lights are on or the headlights there is no difference for the blinker. When the hazards are on and I step on the brake they stop flashing and just hold the steady on. The lights do get brighter when the brake is applied.
The bronco was rewired in about 2015 and had the American auto wire installed. To even check the lights I have 25 amp fuses in there so they don’t keep breaking.

 

[DirtDonk]

Be careful with overpowering the protection.
But does that mean you’re saying that prior to this, they were blowing the fuse? You definitely need to track down the short rather than increase the rating of the fuse.

 

[CaliBronco29]

Be careful with overpowering the protection.
But does that mean you’re saying that prior to this, they were blowing the fuse? You definitely need to track down the short rather than increase the rating of the fuse.

Ok thank you where do you suggest on tracking down the short? I checked my grounds and they all looked good.

 

[DirtDonk]

Since the hazards do work, have you tried swapping the flasher units for each other? With the quality (or lack thereof) of today’s modern parts, you could easily have gotten a bad turn signal flasher.

Checking grounds is always a good idea. But grounds, proper grounds that is, don’t cause shorts.
A short circuit is quite literally, by definition, a short to ground.
So one of your power wires has a little too close to relationship with a grounded point.
This often happens with wires inside the column. But you say you replaced the turn signal switch itself? Was it pretty straightforward to run all the wires through the column?
Installation can often scrape one or more wires, so it pays to be extremely careful there.

Another common area to find a short is in the tail light sockets themselves.
Sometimes they get corroded, sometimes they get broken or bent. So check the quality and condition of your rear lamp sockets.
And the front for that matter. You said the rear, but since the front doesn’t work either, you have to check all four as well as other things.

But when all four don’t work, and using any of them blows a fuse, you may have a fault in the main power circuit to the flasher relay. Or or to the column.
Something in common to all four corners.
Does the fuse blow when the turn signal is moved to the left and the right or just one side?

 

[DirtDonk]

And you can ignore the old fuse advice from earlier. In the future, add all the information you can.
Since you’re new and we don’t know you, we didn’t know that you had a completely new wiring harness, and that all four lights didn’t work.
When you get a chance, add that information to your signature line so that we can just look at it and know anytime we’re discussing things.

 

[CaliBronco29]

And you can ignore the old fuse advice from earlier. In the future, add all the information you can.
Since you’re new and we don’t know you, we didn’t know that you had a completely new wiring harness, and that all four lights didn’t work.
When you get a chance, add that information to your signature line so that we can just look at it and know anytime we’re discussing things.

Thank you for that. I appreciate the quick responses as I am working through this problem. I will check the main power circuit and see if I can find any issues.

 

[73azbronco]

sounds like you have a fault to ground. What is battery voltage engine off and on?

Might have a ground through alternator. Can check by disconnecting alternator wire.

You may have a ground in wiring to lights. How do the light sockets look? Clean those up.

Do not try to get lights by increasing fuse size, you will fry something.

 

[Brush Hog]

I had similar problem after installing a complete painless wiring harness. I had scraped insulation off a turn signal switch wire and it was grounding out in column. Turning on headlights would blow a fuse every time. And also remember led lights are polarity sensitive. I fixed some other lighting issues by just rotating bulbs and re installing them.

 

[CaliBronco29]

Since the hazards do work, have you tried swapping the flasher units for each other? With the quality (or lack thereof) of today’s modern parts, you could easily have gotten a bad turn signal flasher.

Checking grounds is always a good idea. But grounds, proper grounds that is, don’t cause shorts.
A short circuit is quite literally, by definition, a short to ground.
So one of your power wires has a little too close to relationship with a grounded point.
This often happens with wires inside the column. But you say you replaced the turn signal switch itself? Was it pretty straightforward to run all the wires through the column?
Installation can often scrape one or more wires, so it pays to be extremely careful there.

Another common area to find a short is in the tail light sockets themselves.
Sometimes they get corroded, sometimes they get broken or bent. So check the quality and condition of your rear lamp sockets.
And the front for that matter. You said the rear, but since the front doesn’t work either, you have to check all four as well as other things.

But when all four don’t work, and using any of them blows a fuse, you may have a fault in the main power circuit to the flasher relay. Or or to the column.
Something in common to all four corners.
Does the fuse blow when the turn signal is moved to the left and the right or just one side?

Ok so I found the short I think. I took off the hazard switch and it was super crusty and dusty. When I cleaned it up and put it back together I and getting 12 volts to my flasher and have all 15 amp fuses in. When I am checking the voltage out of the flasher it wants to start blinking but I am not getting it to work when engaged. Could it be the turn signal switch itself?

 

[73azbronco]

not enough info to determine issue.

 

[CaliBronco29]

Update. I can now get all lights to work properly when I bypass the switch itself. The only source of the issue can be the switch thank you for the help everyone!