Chasing a Dead Short (Fresh Painless Harness)

[mr110]

Hi All,

I am looking for advice on chasing a dead short (first time wiring, and its been a rough experience even with a painless plug and play harness)

-Should I remove all my connections, plug in and test as I go until I find an issue?
-Or test and unplug and I go until I find issues?


I have been working to install a full painless wiring harness, with all new switches. Also with a new 3G alternator and connectors, and new starter solenoid.

This weekend I went to find why I was getting no response from the truck.
-I checked over everything and it's all as is written in the manual (or so it appears)
-So I started testing for power and continuity, with the truck in ACC I get some power...but
-Then tested the continuity between the power in lug on the starter solenoid to the battery ground had continuity.

There is no continuity when off between:
-The 2 pos lugs on the starter solenoid
-Between the power and ground on the alternator
-Between the S and I terminal

I am lost on how to best chase this down.

 

[Dlish]

Little bump on this, there are some wiring gurus here who should chime in soon for you...

I got through the painless kit to, There was one wire that I almost missed in the directions, maybe a larger yellow behind the cluster that needs to be connected even if not using stock amp gauge, easy to miss and I think the harness won't power up with out it

Again just trying to remember what got me when I installed it.

Hopefully one of the experts gives you more info soon

 

[Bronco Maniac]

You can call Painless. I called a couple of times when I was installing mine and got excellent customer service from very knowledgeable techs.

 

[DirtDonk]

I'll PM Eric to come over and join the conversation too. He's the original designer and the writer-of-instructions for this particular Painless harness.

My first recommendation though, would be to NOT use continuity/ohms as your testing method. At least not for everything.
Sometimes you get continuity with a meter, but that does not automatically mean it's a short-circuit. When the switch is closed you have continuity. That's just how things work, electrical-wise. If you have the correct setting on the meter though, you will usually see a specific ohm reading which indicates the resistance of whatever the load is on that circuit.
With the ignition switch power so many circuits however, your reading may look like zero ohms when there really is some there. Which would indicate that it is NOT a short-circuit.

At least that's the way I can put it into words. I know that ohms have fooled me many times when looking for a fault. I still use that meter setting of course, but not for near as many things as I used to.
Someone will have the real skinny on all that though, and hopefully they'll clear it up.

In the meantime, describe what is, or is not happening.
For instance, are you blowing certain fuses? Do you not have any power at all? As Dlish said, there are some things that must be connected for anything to work.
But if you get power, then have a blown fuse shutting things down, you would have a short in that case.

Let us know. In the meantime maybe ericOo1 will chime in.

Paul

 

[Broncobowsher]

Presume this is a fuse that pops the moment it goes in. That should at least narrow down what circuit it is.
Put a light bulb in where the fuse is at, a bigger bulb like an 1156. It should be nice and bright with a dead short. Now start pulling stuff on that circuit. When the bulb goes out (or at least drops a lot of brightness) you found something.

 

[kenny65]

Powerprobe.com
Worth every penny!!

 

[Teal68]

Without more info I'm guessing the yellow wire behind the gauge cluster is not connected or a bad ignition switch.

 

[eric0o1]

have any fuses popped?
have you tried testing the different circuits as outlined in the manual?

 

[Pa PITT]

I'll say do as Bronco Bowsher said. But I'll bet it's the wrong senolide .. Back when I had my parts store. I SAW AN ISSUE many times When people just wanted one of those Ford senolide , you know their all the same.
Well guess what their not all the same. One has a Grounded Base & The other doesn't have.
... So after doing what Bowsher said . Jump to the senolide.

 

[mr110]

Thanks for all the replys.

I checked all the fuses, none have popped in the fuse block, the mega fuse and the inline fuse from the alternator to the solenoid is good as well.

I checked the back of the cluster. There is no yellow wire there, there is one going into the ignition. The only open yellow is unused and capped form the voltage regulator (not uses, using internally regulated 3G)

The Black/Yellow (972) and the Black (972) wire are connected through the ammeter pass though on the cluster.

 

[mr110]

Without more info I'm guessing the yellow wire behind the gauge cluster is not connected or a bad ignition switch.

how would i test for a bad switch?
I guess i have the old one, it worked before i pulled it out. I could just use that.

 

[mr110]

Presume this is a fuse that pops the moment it goes in. That should at least narrow down what circuit it is.
Put a light bulb in where the fuse is at, a bigger bulb like an 1156. It should be nice and bright with a dead short. Now start pulling stuff on that circuit. When the bulb goes out (or at least drops a lot of brightness) you found something.

I am very new to all this wiring. Testing with bulbs and jumping solenoids is a bit confusing to me. Ill dig into it for sure and see how to do it!

Thank you all so much.
Its raining in Oregon now, any my rig is outside. But ill keep checking and looking as I can to try and keep my replies up..

 

[eric0o1]

after reading your original post, I guess i'm confused as to what your issue is. Are none of your switched ign. power circuits working? No power at the fuse block?

 

[SHX669]

What do you mean by " no response from the truck " - no power anywhere or the engine won't turn over when you try to start it ?
If the later then I'd first look to see if the two NSS wires are connected . Either a butt splice or through the tranny Neutral Safety switch.
Only as a side note ; I usually restrict my electrical work to changing batterys ; and only if + and - are clearly marked -LOL . That being said I found the Painless Harness fairly easy to install especially with the awesome Manual it came with . Read through it I'm pretty sure some of the trouble shooting techniques will help. In fact I still use the Manual for reference even when working on Broncos without a Painless Harness.

 

[czabel]

Hey guys, I'm a friend of mr110 who went to try and help him for a few hours. Hopefully I don't further muddy the waters.

SHX - no response in this case means the starter wouldn't even try to get going. There were also no lights or anything else.

eric - Embarrasingly, I don't remember checking any of the switched power circuits other than the S post on the starter solenoid, but that one was behaving strangely. I think I remember it starting around 1.5V and climbing slowly. Either the DMM we had was absolute garbage, or something really strange was happening. I've only ever seen large electrolytic caps behave like that.

We checked continuity from Batt+ to GND in a number of places, and found that we had a large issue - either we've got a short somewhere or a bad meter/methodology. After thinking more about it, I'm leaning toward the latter combination. We saw no arcing when we connected the battery terminals that would suggest a straight short from Batt+ to GND through the truck.

After I had to leave, I told him to check continuity between the S and the I posts on the starter solenoid - and he got no continuity. This tells me it's broken, because that's a simple electromagnet (a long wire) and shouldn't confuse even the dumbest of DMM. Am I incorrect here?

At this point, I really just want to get back over there with a decent meter and start again, but I don't know when that will be. I'm thinking he might want to just disconnect things and start with the simplest circuits first, ensuring one works before adding another.
What do you all think?

 

[DirtDonk]

...We checked continuity from Batt+ to GND in a number of places, and found that we had a large issue - either we've got a short somewhere or a bad meter/methodology.

Maybe we're on the wrong terminology here. A dead short on a circuit will melt the wire or hopefully blow a fuse first, on any wire you connect.
The word "short circuit" means literally running from positive to negative directly (taking the "short" route) without first running through a load that has resistance.
No resistance between positive and negative will certainly let you know with fireworks of one kind or another.

A broken circuit on the other hand (going the long way round and not finding an end) will give you zip, zilch and nada without the fireworks.

We saw no arcing when we connected the battery terminals that would suggest a straight short from Batt+ to GND through the truck.

That's a good sign. I think!
So you're looking for the reason that there is no power. The Black w/yellow wire being connected behind the ammeter is the "Yellow" wire the others were talking about. Some harnesses (not Painless in this case) use Yellow, so that's the confusion I think.

If you connect the battery positive to the starter relay, and the negative to BOTH the engine and the body, then it should be fairly easy to track down where the power isn't and where it is. Therefore where it stops.
Is there a 10ga Black wire with a Maxi-Fuse connected to the battery side of the starter relay?

After I had to leave, I told him to check continuity between the S and the I posts on the starter solenoid - and he got no continuity. This tells me it's broken, because that's a simple electromagnet (a long wire) and shouldn't confuse even the dumbest of DMM. Am I incorrect here?

Not a bad idea, but wrong information you're looking for. When just sitting there, the "S" and "I" posts on the starter relay/solenoid have no connection.
It's ONLY when the relay is energized by the key in START, when you hear the click (and the starter spinning if it's connected during the test) will you see a connection between the two. And even at that, there might not be a connection.
The reason i said "may not be" a connection is that what you're looking for is continuity between the big BAT side post (where the positive battery cable is) to the "I" post. That would tell you that this function is good.

However, the I post has nothing to do with the starter cranking, or electrical power getting to any circuit other than the ignition coil. Only power at the S terminal will energize the starter relay and then the starter. The I post is only for an additional jolt to the coil for more spark energy at the plugs for easier starting, especially when cold.

You can test the starter relay/solenoid by touching a small jumper wire between the battery positive and the S post. If you hear a click, the relay is good.
If the starter motor is connected, then you will hear a click and immediately hear the starter spinning (so watch out for your fingers and toes!) and should be able to read battery voltage at the I post at that point.

Good luck! Thanks for helping a bud out on what can be the most "fun" part of a project. Wiring!

Paul

 

[DirtDonk]

Oh, and I meant to ask for some pictures. Any chance you can shoot a few of the engine compartment, especially around the starter relay and the alternator?

Since you're not a contributor, you can't upload images directly from your phone or computer. But if you use online image hosting sites you can use one of them and put a link in your posts for us to see the pictures.
Or you can e-mail photos to me (or anyone with a yellow "contributor" below their username) and we can post them up.

If you're going to be doing this a lot though, the 13 bucks annual fee is actually pretty cheap for the benefit. Up to you though. Not always wanting to throw money at an internet forum when first joining I'm sure.
But if you use it enough, you'll come around...

Paul

 

[DirtDonk]

Eric, did you ever change the fuse design for the cabin power, or are you still using Maxi-Fuses in the kit?

Paul

 

[eric0o1]

So are y'all just testing stuff before any physical testing of switches and circuits? From experience and from dealing with others who have tried that, you end up chasing your tail, so to speak. I would honestly just start testing the system as outlined in the manual, either with or without the battery charger that's mentioned. Connect the battery and start testing systems, it's only when an issue arises, and after I've tested every circuit, that I break out the volt meter

I think you're seeing continuity between battery + and ground because of things like the radio, a clock, or any other accessories that are connected to a battery power source. Pull the maxi fuse and see if you still see continuity.

I don't believe the S and I will have continuity on the starter solenoid until the solenoid is energized.

Edit- wow Paul, you added a lot in the time it took me to write my response. The harnesses are still shipping with the Maxi fuse, I will switch it over to a MIDI fuse at some point, but right now I've got other new and old harnesses that need more attention (There's only been 2 of us here handling product design/rehab for the past several years)

 

[czabel]

DirtDonk - I'm sure mr110 can upload some pictures - not being a Bronco fan I probably won't be signing up. I just happened to have experience using a Painless kit on my dad's Mustang, so here I am!

As for the solenoid - I guess I picked up some false information along the way. Looks like Ford solenoids are grounded via the mount-frame connection, yes?

mr110 will be able to better answer the question regarding the Maxi-Fuse, but I believe that is how it was connected, yes - that's the #916 wire according to the manual, correct?

eric - No, testing began with the procedure found in the manual, we broke out the DMM when nothing seemed to be happening. I think you may be right about chasing our tails though. And I stand corrected on the solenoid wiring.


I think the next step will be connecting BATT+ to the starter solenoid, unplugging the Maxi-Fuse and checking that we see 12V only on the BATT+ side of the starter solenoid. Then, plug in the Maxi-Fuse and check #972 near the Ammeter for 12V. Assuming that's good, move to #934 on the ignition switch, check it there, and check the function of that switch using that terminal E and terminal A that goes through the Neutral Safety Switch to the starter solenoid S terminal (wire #919). Switch in the START position should give 12V on S.

Should be pretty straightforward, unless I'm missing something dumb.

Thank you both for chiming in so far, this is the first time I've had to troubleshoot a car like this (the Mustang harness worked right off the bat...)