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electrical short

brncofinatic

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Dec 8, 2004
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all you gurus out there I think I have one for you. Hopefully someone has seen what I am about to explain. So yesterday I fired up the bronco for the first time in 14 years. New everything, centec wiring harness, new crated long block engine, new pretronix HP ignition. First crank and it fired up and ran (needs some timing) Everything was working except no oil pressure on gauge, so I removed electrical sender and hooked up a manual gauge started it back up and had 80psi of oil pressure, shut it down (as I have other issues to fix) and noticed my right blinker indicator was blinking. Looked in the front and sure enough the front right blinker is blinking, looked in the back and no blinker. Turned the key on and tried the blinkers both right and left both function correctly, but my front right was blinking the entire time. Unhooked the battery, re hooked up the battery and still blinking. Started it back up and noticed the blinking changed pattern while it was running, would blink then stop for a few seconds then blink again. Shut down the engine and it went back to a normal 1 second blink. I am thinking it has to be a short coming through a ground as only the front is operating. anybody seen anything like this or anybody have any idea. appreciate any and all ideas. Tahnks Jerry
 

56f100bbw

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Recently I had the same issue I had to change the lightbulbs the contact on the back was dented in from sitting old bulbs , that did the trick for me you might try it
 
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brncofinatic

brncofinatic

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well that is easy enough, I will check and see. the lights are all new also and didn't do this when I checked all circuits but pull the bulbs and see. Thanks Jerry
 

onpier55

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Roseville Ca
My guess is it’s in the steering column. Or wired hot to blinkers. Should be key hot to blinkers. I had a turn signal switch go bad in months.
 
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brncofinatic

brncofinatic

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update for all. It is the hazard circuit, not blinkers. I checked the functionality of the hazards on the column and they worked fine. I then disconnected all grounds to the light that is flashing and it still flashed. Next I unhooked the steering column connection and it still flashed, so it isnt in the steering column (which is also new, flaming river). So worked on all the other stuff to fix today, but still haven't figured out the flashing right blinker, which is the hazard not blinker, just wondering if it could be the flasher relay? might be worth a try. to be continued
 
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brncofinatic

brncofinatic

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update, got the light to turn off tonight by unhooking the Pertronix plug in. Still reading wiring schematics trying to figure out how power is getting to the light wire. Haven't figure that out but working on it. Anybody have ideas?
 

Rustytruck

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Feb 24, 2002
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10,875
check all your green wires with red stripe, 12 volt power wire from ignition goes to multiple connections. swap your 2 flashers and see if the problem follows the swap. from the battery negative do you have a ground wire to the body and engine Block. very important grounds the mounting of the starter solenoid to the body, factory voltage regulator mount to the body, the ground wires to the turn signal and the head lights to the body and out back at the driver side rear bumper at the taillight harness there is a ground to the frame. mounting screws for the taillights and on the tail light housings the rivets holding the tail light housing pieces together. there has to be a good ground for the gauge cluster.
 
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brncofinatic

brncofinatic

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I do have all those grounds in place except maybe the gauge cluster, I will check that one. swapping the wires is a good idea. I can try that if it comes back. I did get it to stop and is is related to the Pertronix ignition. I disconnected the wire harness from the HP box and the reconnected it and the light quit blinking. I haven't had much time this week to dive into it but maybe today. I will go back and check those other wires also. Thanks Jerry
 

ransil

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Sep 6, 2003
Messages
8,122
update, got the light to turn off tonight by unhooking the Pertronix plug in. Still reading wiring schematics trying to figure out how power is getting to the light wire. Haven't figure that out but working on it. Anybody have ideas?
It might be using it as a ground path,check your grounds

Sent from my SM-G960U1 using Tapatalk
 

DirtDonk

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It is the hazard circuit, not blinkers.

How did you determine that again? I'm not sure I read anywhere in the posts, so just checking for my own information.

I checked the functionality of the hazards on the column and they worked fine.

This might indicate then that the fault is not in the hazards either. But no guarantee just yet.

I then disconnected all grounds to the light that is flashing and it still flashed.

That sounds to me like it indicates another problem. If you disconnect the ground then that light should go out. Period.
So this tells me that it's hunting (and finding) a supplementary ground somewhere. This is the right front, correct?
Is this a new light housing? They're well known for being wired backwards, but it sounds as if yours might also be cross-wired somehow and getting a ground elsewhere. Although I suppose if you left it bolted to the grille, it's grounding through the housing. Not sure if this is a good thing or not, but it sounds like right now it's not.

Next I unhooked the steering column connection and it still flashed, so it isnt in the steering column (which is also new, flaming river).

Definitely rules that out. Good to know.
So power is getting to the light circuit through a short with something else.

just wondering if it could be the flasher relay? might be worth a try. to be continued

No. If it was, then they'd all be flashing all the time. Not just one, because the one single flasher relay feeds all four corners (through the steering column as a matter of fact) so if all of your 4-way functions work when you flip the switch, the relay is fine.
However, a short is a short and are often in the strangest places, so if you did not already then do what Rustytruck said and swap the two flashers to see if things change at all.

got the light to turn off tonight by unhooking the Pertronix plug in.

So now you're on to something. But now you have to review just exactly how you connected the ignition and to what circuits and may even have to undo some of them to trace the problem.
Normally there is ZERO possibility that an ignition component can effect ANY lighting component. But since this is aftermarket, you need to dig into it further to find out the common issue.

Still reading wiring schematics trying to figure out how power is getting to the light wire.

The schematics won't matter because you have a Centech harness and that has very little to nothing in common with factory wiring. So a wiring diagram for a Bronco from one of the books no longer applies.
Unless you found a schematic that someone put together for a Centech? If so, post it up!

check all your green wires with red stripe, 12 volt power wire from ignition goes to multiple connections.

No more Green w/red stripe wires unfortunately. Centech harness, so just solid colors for 99% of the wiring.
However, Green is still a common accessory wire. We just now have to find out which ones are hot in ACC as well as ON, and which ones are hot only in the ON position.
brncofinatic, is your ignition system hot in ACC? If so it should not be, because you can burn things up while you're listening to the radio or just working on the electrical system in ACC mode.

Find out if any of your ignition feeds, if any, have power with the key OFF or in ACC
I forget, does the light flash all the time? Or just when the key is in one of the active positions?

swap your 2 flashers and see if the problem follows the swap.

Did you do this yet brncofinatic? If not, even though it is unlikely to show a fault with the relay, it might just highlight something at this point!

from the battery negative do you have a ground wire to the body and engine Block. very important grounds the mounting of the starter solenoid to the body, factory voltage regulator mount to the body, the ground wires to the turn signal and the head lights to the body and out back at the driver side rear bumper at the taillight harness there is a ground to the frame. mounting screws for the taillights and on the tail light housings the rivets holding the tail light housing pieces together. there has to be a good ground for the gauge cluster.

I do have all those grounds in place except maybe the gauge cluster, I will check that one.

You've added a ground to the body from the battery? From the engine to the body? From the body to the dash possibly? Any others you added? Ford did not have many obvious ones, but they're needed. And not just the ones included in the Centech harness. Those don't count in this hunt.

There is no separate ground for the cluster unless you added it yourself. Which is a good thing to do no matter what. It normally grounds through it's mounting screws to the dash. But this is not always enough with older rigs.

And speaking of which... Is your Bronco rusty? Has it been painted? More than once? What about the dash and interior? Painted too?

I did get it to stop and is is related to the Pertronix ignition. I disconnected the wire harness from the HP box and the reconnected it and the light quit blinking.

Got a pic of your under-hood setup we can see?

Paul
 
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brncofinatic

brncofinatic

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Thanks for all the ideas. I will try and answer all the questions. First the battery is grounded to the engine, the engine to the frame, the frame to the body. All lights are new and each one is grounded individually. There is no rust as most the front end is new metal and yes it has been painted but everywhere I have a ground I have scraped the paint off. I have not checked for a ground at the cluster yet (been working on transfer case today). The light that was flashing was the right blinker/flasher light, only the front. It is shorted in the flasher circuit as that is the relay which is getting power. If I unplug the relay the flashing stops. If I plug it back in it starts again. This is with the key in off and ACC. If I try the flashers all flashers work, turn them off and only the front right is flashing. I got it to stop by unplugging the pertronix ignition and plugging it back in. This happened after I fired the engine up for the first time. Prior to running all circuits checked out, found no shorts, only after I started it did this happen. I was going to work on the timing this afternoon and get it going again, I will let you all know if it comes back (assuming it will) I will also try to get some picks of under hood setup and post for you all to see. More to come. Thanks Jerry
 
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brncofinatic

brncofinatic

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forgot one, I have not swapped the lights yet as the flashing stopped. If I get it back this afternoon I will do the swap and see what happens.
 
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brncofinatic

brncofinatic

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gotta love Saturdays! so here is the update, the short came back. only right front blinker flashing. I did do the light swap and the short did follow so it is in the wire. Verified it wasn't a short in the steering column by un plugging and checking power, it was coming from harness side not steering column. It was the blinker/flasher wire so traced that back to the fuse box, pulled the fuse on the blinker and the light still blinked, no key on. Put that fude back in and pulled the fuse for the flashers and light quit blinking. I Then went to the fuse panel and checked wires, all looks good but i did move then and reposition, short stopped hasnt come back I ran the engine multiple time to day after repositioning wires and still no short. I am thinking it isd a short in the actual fuse panel from Centec. anyway Bronco is running, and no short as of now. I will try to post pics of the set up, never done that so I hope I can figure it out. Thanks Jerry.
 
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brncofinatic

brncofinatic

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so can someone tell me how to attach some photos. I took some today so you all can see the underhood setup but cant figure out how to attach them.
 

Boss Hugg

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I read a few posts and skipped to this comment:

Years ago, we had an automatic bronco that ran great until you stepped on the brake pedal with the headlights on. We searched and searched. I PULLED THE DASH HARNESS COMPLETELY OUT LOOKING FOR SHORTS. Long story SHORT, it was lack of body ground. The PO had pulled the bolt off the battery cable that grounded it to the body. We figured the brake lights were grounding thru the ignition which took power away from the ignition, so the engine would stumble.

This may or may not help the OP, but it's good info for someone somewhere in the future.
 

DirtDonk

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This may or may not help the OP, but it's good info for someone somewhere in the future.

Absolutely! All experiences are welcome on the forum. If it helps just one person the forum did it's job.

so can someone tell me how to attach some photos.

It's relatively straightforward, but takes a few times for it to actually become "easy" to do!
You're a contributor, so you're good there.
1. You need to first click on the "Go Advanced" tab below the reply window, or the "quote" button in the message. Which just takes you to the same "go advanced" screen anyway.
2. In the advanced screen, just below and to the left of the reply window is the "upload photos" button.
3. In the pop-up window that results, you can browse your device and double click the file, or single click then hit the "save" buttons. Multiple photos are ok with one session.
4. Click on the "upload" button in that window.
5. Finally, put the cursor where you want the photos to appear in your message, then go up to the paperclip icon and open up that menu to see your uploaded photos. Click on each one you want to show and the link will appear where your cursor was.
6. Finally just hit "submit reply" and the photos should show up in your message.

There are two or three other ways to do it as well (and they're probably all described in the "how to upload photos" thread hereabouts) but that's how I always do it.

Paul
 
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brncofinatic

brncofinatic

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here are some pics of the wiring
 

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brncofinatic

brncofinatic

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had to throw one in of the bronco. Same bronco as my garage pic shows just 14years of work and a few upgrades.
 

DirtDonk

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Well there's your problem right there. Your wires get pinched when you close the hood and door!;);D
Just kidding. Figured I had to joke about the wires hanging over the core support and hanging out the door, even if those are tool cords, test wires, or just excess waiting to get tidied up a bit.

But would that it was that simple!

Good luck on the tracing the fault still. Odd that something is connected between the ignition system and right turn signal lamp. But they are in the same corner of the vehicle, so maybe there is something tied in there that we just can't see yet.
Did you say that only the front lamp is effected? Or is the rear lamp lighting up too? I'm guessing front only, but wanted to be clear on it.

Thanks.

Paul
 
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