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Keep blowing my turn signal fuse

38K views 48 replies 26 participants last post by  Aggrokasper 
#1 ·
Hi all,
I'm suddenly running into a frustrating issue. I'm not sure what's causing it, but the fuse for my turn signals (not the flasher) keeps blowing.

I'm not sure what's causing it, and they'll work for a while, but then suddenly....no turn signals. I'll pull the fuse to look and it's blown.

Any ideas? I've had this truck for nearly 7 years and have never had any electrical issues, so I'm not too well versed in tracking them down.

So far, though, I can't find any one thing that causes it. Tried turning on and off various different systems, like the door lights, windshield wipers, starting it, turning it off, etc. Ie. systems that randomly change. Nothing seems to do anything.

Then, I'll just suddenly notice while driving....they've stopped working again and the fuse is blown.



Thoughts?
 
#4 ·
on my 86 the turn fuse kept blowing but it was the hazard switch that caused the problem.small plastic cover on side of switch kept shorting out against wheel
 
#5 ·
I checked my trailer wiring (it's only about a year old) and it was tip top. Not sure what to check on my hazard switch, but on that point, the hazard lights still work. Just not the individual L/R.

Thoughts?
 
#9 ·
The only thing I've done in the last few weeks was pulled the instrument cluster out to look at some information printed on the back of it. It just has the one big plug (which I've since double checked to be sure it was in securely). Other than that, this issue has come out of the blue. No working on wiring, changing bulbs, etc.

I also can't pinpoint when it happens. The signals will work for a day or so, and then I'll just notice that they're not coming on. Fuse blown. There isn't anything I've found that I can do that results in immediate fuse blowing.

The trailer wiring is a simple four prong plug, and the connections are all good.



Jasonhughes2009 said:
id put my money on the multifunction switch though
Which switch are you referring to?
 
#12 ·
I'm not sure what switch you're talking about. What switch is it? (Not necessarily what it looks like.)

ad5mb said:
I had the same problem. replaced the fuse with a 20 amp 120VAC circuit breaker. works fine, lasts a long time, has very few moving parts.
Hope it doesn't come to that. I'd rather track down what's causing it first.
 
#13 ·
The multifunction switch referred to in post #8 is the combination turn signal/windshield wiper, etc. switch.
 
#14 ·
The 80-86 is a bit different and those are all independent of each other.

There's two pull knobs on the dash. One's the headlights and dome light. The other is the windshield wipers.
The highbeam switch is on the floor.
And the turn signal switch/lever is on the column.

I *think* they're all independent systems and have different fuses.
 
#15 ·
Hi everyone.

Any more ideas? Are there any systematic ways I can go about tracking this down? Could anything have happened when I removed and reinstalled the instrument cluster? (I've confirmed it's fully plugged in, but still).

I'm not further to solving this and still have no turn signals.
 
#16 ·
yo AB,

Brake, Turn, Hazard Lights Inoperative, Similar to 80-91 Bronco & F-Series;"...have a friend stand behind your truck and when you are pressing the brake pedal move the turn signal arm ever so slightly, if the brake like comes on, your switch is shorted out and must be replaced..."
Source: by Ford via miesk5 at Ford Bronco Zone Forums


Only other thing I can recommend now is to pull connectors and use a meter to rest for shorts on each conductor using the only diagram I have right now;
Turn, Tail, Brake, Head Light, Hazard & Ignition Wiring Diagram for 84 Bronco & F-Series (partial); "...Similar to 80-91 Bronco & F-Series..."
Source: by Steve83 (Steve, That dirty old truck) at http://www.supermotors.net/clubs/superford/registry/media/714912_1


Turn Signal Switch Connector Location in Parts Break-Out Diagram in an 83; similar to 80-91
Source: by Seabronc (Rosie, Fred W) at http://broncozone.com/index.php?app...=attach&attach_rel_module=post&attach_id=3014
 
#17 ·
I actually had the same problem occur when I was messing with my alarm system one day. I have a 95 and I use emty fuse areas within my inner fuse panel to power my alarm. Anyway, I had grounded out a different fuse on accident and this caused my turn signals not to work, while my hazards still worked.

Are you saying your blowing the round fuse? Mine was never actually blown, so make sure you don't have a wire grounded somewhere.

I'm at work so I hope I wrote that clearly, just my .02
 
#19 ·
Are you saying your blowing the round fuse? Mine was never actually blown, so make sure you don't have a wire grounded somewhere.
It's actually the 15amp fuse in the fuse panel that keeps blowing.

However, someone at the parts store suggested that since the fuse for the turn signals keeps blowing but the hazards still work, that a 'quick and easy' check would be to swap the big round flasher fuses to see if a dying turn signal flasher keeps blowing the fuse.

I tried it and it's been about four days and my fuse hasn't blown again.
Hopefully it'll stay that way. If so, I'll just buy a new flasher.

The wire runs from the dash area to the back of the truck, and if it's anything like mine was, it's inside the frame rail under the truck. It could have gotten snagged on something or the outer jacket could have been rubbed off because your trans mount is wasted and every time you punch it from a standing stop you move the wiring harness just a little bit.
The tabs on my transmission have broken off, so it's not even held down anymore. So yeah....it probably moves around.

If the above doesn't work, I'll check the wiring under the truck. :thumbup
 
#18 ·
The wire runs from the dash area to the back of the truck, and if it's anything like mine was, it's inside the frame rail under the truck. It could have gotten snagged on something or the outer jacket could have been rubbed off because your trans mount is wasted and every time you punch it from a standing stop you move the wiring harness just a little bit.

Get an ohm meter/multi meter and and some 14 gauge wire and check resistance. If it's high then you've likely got an intermittent short somewhere and that's why it works for a while then blows.
 
#21 ·
Wish I had a definitive answer for you. I was blowing turn signals every day/other day and then it just suddenly quit and hasn't blown a fuse in probably a month now.
I'm wondering if I may have shook the right wire to stop the short while I was searching underneath.
 
#22 ·
I will keep that in mind. They worked fine for the first day after I replaced the switch. Looks like I get to tear the column apart again to inspect everything. I hate unpining and repining connectors.
 
#23 ·
You should be able to work the connector out without unpinning. It's a tight fit and has to be turned just right, but I've done my 86 a couple times.
And try switching flashers, they can cause fuses to blow. When I got my 86 it was a mess in the column. The turn signal switch would blow fuses when I hit the brake. After many hours checking wiring and putting them right, and fuses, and a turn signal switch and bulbs it all works.
 
#24 ·
I had the same problem with my 94. In fact that's why the price was so low. The guy traded it in and even the dealer couldn't figure it out. The problem was when they built the truck they pinched the wiring loom in the column mount and after a while it wore off a little insulation and pow the fuse would pop. Easy fix once I found the problem.
 
#25 ·
mine was do that samethine but the problem was the factory wire harnass next to the gas tank. The harness was sagging and rubbed on the frame until the insulation was gone. I would check the main harness near the drive side rear corner of the gas tank. This harness feeds the trailer lights and rear turn signals.
 
#26 ·
Well, I determined that it was only blowing the fuse while signaling right. I tore the column back apart, inspected the switch, and every inch of wiring that I could lay my hands on. No damage to any wiring, no burn marks from anything grounding out. I put everything back together, and the f***er works perfectly now. I did absolutely nothing to correct the problem, and it's back to normal. Guess I will just have to keep my eye on it.

On a side note, I discovered I do not need a steering wheel puller to remove the wheel, just a little bit of upper body strength.
 
#28 ·
I had a problem with my horn fuse blowing. By accident I discovered it was happening when I turned the wheel. (I heard it pop while I was backing out of the driveway). I replaced the "horn ring/turn signal switch) and it is now good.
 
#30 ·
I have a slightly different turn signal question.

My turn signal lever/switch is broken. At first the problem was that it would not click into the turn position right turns. I had to hold it in position with my hand. Then the same thing happened with the left turn signal.

Now the turn signal lights no longer come on either. Not sure if it's related to the lever switch problem or something else.

About that lever switch, do I have to remove the steering wheel in order to repair or replace the switch?
 
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