Fixing Connector Problems -- A Suggestion

[AZJeff]

One of the common issues that crops up here on Comanche Club are electrical "gremlins" due to poor electrical connections.  Often these can be traced to the actual connectors in the wiring harness itself.

 

In a former life, I was a mechanical engineer who spent a lot of time around electrical connectors, so I have a decent knowledge of what makes a good connector.    I won't mince words--the connectors Jeep used in the 1980's were very primitive.    The designs Jeep used were just very prone to environmental damage, which makes the connectors intermittent.

 

On my MJ, I have chosen to replace connectors that don't have a specific interface to a component.  What that means is, if a connector is in the middle of a wiring harness (with both a male and female end), whenever I am working on that section of the harness, I cut out and replace that connector with a more modern type, one that has modern environmental sealing built into it.

 

What I have been using is a connector series made by "AMP", which has a long history of being a supplier to the automotive industry.    I have used products from AMP in my career, and this design is perfectly suited for replacement use in vehicles. This series is sold on Amazon, and the connectors come in a variety of sizes (number of connections).  

 

Each connector already has a "pigtail" of wiring on it, so no special crimping or installation tools are needed.   To make reliable connections, one would either need to solder these connectors  on to the existing wires, or use the type of butt splices that have a heat-shrink covering that provides a waterproof seal over the splice.  (I choose soldering, since I know it's the most durable.)

 

Here is a photo of a few of the sizes of the connector family, for reference.   They go by the "MUYI" brand name.  They are made in China (of course), but they are licensed from AMP.

[gogmorgo]

These are decent connectors, used everywhere on modern cars and very available. Specifically these are the AMP Superseal 1.5 series.  Our tiny little parts store in the middle of nowhere usually even has some in stock. You can also get re-pin kits from a variety of manufacturers for people who prefer a cleaner install, not to mention a proper crimp is going to be more reliable than trying to get solder to stick to old oxidized corroded wires. That said, solder and heat shrink is definitely my preferred splicing method, and the extra length of wire added is usually helpful as well. 

[Minuit]

I could get fired up about connectors and wiring best practices and type until my keyboard breaks, but unfortunately I have to go to bed soon, so I'll just throw some of my own things out there:

 

- 90% of the connectors on an MJ are utter trash. If they give you problems they're not worth keeping.

 

- Crimp enthusiasts and solder enthusiasts love to get on their respective holier-than-thou high horses and proclaim themselves the best. This is a dumb argument, and it's one I am long tired of, so I'll sum it up: To make a quality joint, crimping requires good quality tools and supplies and an understanding of how to use them. Soldering requires good quality tools and supplies and an understanding of how to use them.

 

- I prefer leaded solder to lead-free solder (just for the love of all that is holy, wash your hands after handling it), and open-barrel crimp terminals to closed crimp terminals.

 

- Quality connectors can be a "pay to play" game. It's hard to go wrong with AMP. All of my quick-connect, ring, etc. terminals are AMP. Expensive, but worth it. Molex makes a good line of super cheap, light duty connectors as well, and the contacts crimp really well with generic crimping tools. I bought the official unsealed Metri-Pack 150 crimper to do radio harnesses with. I paid over $150 for it, and it only does one type of terminal. But it does a damn good job.

 

- Here's a good site for colored and striped automotive wire. They're not joking about that same day shipping either.

 

- Aptiv connectors, especially the 150 series (and maybe the old Weather-Pack connectors they're descended from), are probably about the best entry point to doing truly OEM-style harnesses I can think of, because a generic crimping tool will do an "OK" job on them, they're used on our trucks, reasonably small for their pin count, rated at I think 14 amps per circuit, readily available in many variations, and aren't all that expensive.

 

- Use the right connector for the job! If I see one more person using an unsealed spade terminal in an exterior application I will reach through my screen and slap them silly with the package they came in.

 

- I can not think of a single good time or place to use these things:

They provide no environmental protection, take up way too much space, look ugly, and most people don't even use them properly anyway. Don't use them! If you must use a butt splice,

[gogmorgo]

1 hour ago, Minuit said:

- I can not think of a single good time or place to use these things:

They provide no environmental protection, take up way too much space, look ugly, and most people don't even use them properly anyway. Don't use them! If you must use a butt splice,

Go on?

 

I’ve used those cheap butt splices for mock-up and testing, but only when I knew I was just going to tear the thing apart and eventually add a connector or something, never for a permanent install.

 

One other thing to be said about heat shrink tubing is it provides some strain relief for your splice, in addition to making clean and compact weather-proofed connections. Probably the biggest argument against those butt connectors next to lack of environmental protection is that you’re creating a stress riser that will lead to a broken wire if you don’t provide some form of strain relief. Most connector pins do this by also crimping to the insulation further up on the wire to help prevent unwanted movement around the electrical crimp, but those butt connectors have nothing.

[AZJeff]

I understand the comment about corroded wire being difficult to solder.  I have a work around I have used for years:  crimp on solderable butt splices.

 

Once the wires are stripped, then a crimped sleeve is used to attach the two pieces, and then the whole assembly is soldered.  Finish up with heat shrink, and the joint is as good as new.

[OldManComanche]

I agree with the thought about the poor quality of wiring on our trucks. I have been fighting the random high speed idle problem for a while now. I used a produce called DEoxIT D100 ( it comes in a small plastic bottle with a metal spout) to improve the electrical connection on all of the engine connectors. I used a little compressed air to blow out any dirt in the plug ends. A single little drop on each wire pin end will do. Do not over do it. This stuff will conduct electricity, so if you put too much on the plug end it will short to the neighboring wires. Basically what you are trying to do is make a good electrical connection in the plug, no resistance.

This should be used as a diagnostic tool. It took less than 10 minutes to treat all of the connections going to the engine.  

Truck has run perfectly since I did this. If I have problems in the future I will do as AZJeff says: replace the plug ends and soldier the connections. 

 

[gogmorgo]

4 hours ago, AZJeff said:

I understand the comment about corroded wire being difficult to solder.  I have a work around I have used for years:  crimp on solderable butt splices.

 

Once the wires are stripped, then a crimped sleeve is used to attach the two pieces, and then the whole assembly is soldered.  Finish up with heat shrink, and the joint is as good as new.

Usually I try to scrape back the oxidization and that usually gets it solderable, although it's difficult to on multi-strand wire without sacrificing some strands.

The uninsulated crimp butt joints do work pretty well, especially when you can't stretch the wires out long enough for some facsimile of the western union splice and it's going to be problematic to add a length of wire, like if you've got a tightly packed loom. I do sometimes avoid soldering them though just because if I'm using one I typically don't have a ton of real estate to get my heat shrink tube far enough away from the splice to avoid prematurely shrinking it with the heat of the solder.

[AZJeff]

1 hour ago, gogmorgo said:

Usually I try to scrape back the oxidization and that usually gets it solderable, although it's difficult to on multi-strand wire without sacrificing some strands.

The uninsulated crimp butt joints do work pretty well, especially when you can't stretch the wires out long enough for some facsimile of the western union splice and it's going to be problematic to add a length of wire, like if you've got a tightly packed loom. I do sometimes avoid soldering them though just because if I'm using one I typically don't have a ton of real estate to get my heat shrink tube far enough away from the splice to avoid prematurely shrinking it with the heat of the solder.

Wanna know another way to clean up oxidized copper wires?   Cleaners like "CLR" or other similar mild acids will eat away the oxidation.   Of course, one needs to make sure that the cleaner is flushed away with water so the stuff doesn't continue to eat the copper wires.

[Minuit]

If you must solder "vintage" wires, additional flux beyond what's in the solder is a near-must IMO. My personal preference is Kester 186, which is a mildly activated, "no clean" liquid. I use that in little dropper bottles for both wire and circuit board repair and it massively improves the quality of my joints.

[zomeizter]

10 hours ago, Minuit said:

If you must solder "vintage" wires, additional flux beyond what's in the solder is a near-must IMO. My personal preference is Kester 186, which is a mildly activated, "no clean" liquid. I use that in little dropper bottles for both wire and circuit board repair and it massively improves the quality of my joints.

Hand solder instructor here, you should know that flux is your friend! 

[gogmorgo]

Yeah, I inherited some flux when I first started my current job, but it was seemed to make the splices corrode more quickly, and wasn’t as effective as scraping the “vintage” off. Not that anything I work with is particularly vintage, most of our trucks are under ten years old, they just live and work in a very corrosive environment. In hindsight it’s totally possible it’s an acid flux for not-wiring, i don’t know that I ever checked.

[A-man930]

On 2/17/2022 at 10:13 PM, Minuit said:

I could get fired up about connectors and wiring best practices and type until my keyboard breaks, but unfortunately I have to go to bed soon, so I'll just throw some of my own things out there:

 

- 90% of the connectors on an MJ are utter trash. If they give you problems they're not worth keeping.

 

- Crimp enthusiasts and solder enthusiasts love to get on their respective holier-than-thou high horses and proclaim themselves the best. This is a dumb argument, and it's one I am long tired of, so I'll sum it up: To make a quality joint, crimping requires good quality tools and supplies and an understanding of how to use them. Soldering requires good quality tools and supplies and an understanding of how to use them.

 

- I prefer leaded solder to lead-free solder (just for the love of all that is holy, wash your hands after handling it), and open-barrel crimp terminals to closed crimp terminals.

 

- Quality connectors can be a "pay to play" game. It's hard to go wrong with AMP. All of my quick-connect, ring, etc. terminals are AMP. Expensive, but worth it. Molex makes a good line of super cheap, light duty connectors as well, and the contacts crimp really well with generic crimping tools. I bought the official unsealed Metri-Pack 150 crimper to do radio harnesses with. I paid over $150 for it, and it only does one type of terminal. But it does a damn good job.

 

- Here's a good site for colored and striped automotive wire. They're not joking about that same day shipping either.

 

- Aptiv connectors, especially the 150 series (and maybe the old Weather-Pack connectors they're descended from), are probably about the best entry point to doing truly OEM-style harnesses I can think of, because a generic crimping tool will do an "OK" job on them, they're used on our trucks, reasonably small for their pin count, rated at I think 14 amps per circuit, readily available in many variations, and aren't all that expensive.

 

- Use the right connector for the job! If I see one more person using an unsealed spade terminal in an exterior application I will reach through my screen and slap them silly with the package they came in.

 

- I can not think of a single good time or place to use these things:

They provide no environmental protection, take up way too much space, look ugly, and most people don't even use them properly anyway. Don't use them! If you must use a butt splice,

 

Good advice here.  +1 for 4rcustoms wire!

[zomeizter]

On 2/19/2022 at 12:26 PM, gogmorgo said:

"Yeah, I inherited some flux when I first started my current job, but it was seemed to make the splices corrode more quickly..."

Correction: flux is your friend for soldering but ensure you thoroughly remove flux residue after soldering to inhibit conductor corrosion. :)

 

[gogmorgo]

Well I ordered a bottle of liquid flux from one of our suppliers at work, supposedly it was no-clean but the label on the bottle says to flush with warm water. The extra step of rinsing it off and then drying it is a bit annoying, in that it’s extra steps. The flux does help with the “vintage” wires, but not as much as scraping the “vintage” off.

But I figured I would share some stuff off one of our trailers that doesn’t get much use so I hadn’t seen it before. It’s actually pretty cool because trailer wiring is typically pretty jank but all the splices had heat shrink, and all the wiring was loomed nicely, with loom connectors even.

And secured very nicely with riveted-on p-clips 

And I even discovered these cool things that are a step above just grommets for running wire through a panel, these little plastic tube deals so you’ve got somewhere to anchor the split loom with a zip-tie. 

 

But that was where the niceness ended. That anchor tube deal is on the brake backing plate, and after I spun it 180° so it wasn’t pushing the loom straight against the frame, and rubbing every time the suspension moved. I had to fix the wires there on three out of four brake assemblies because of that oversight. The loom had also been secured to the torsion axle… arm, in a few spots, but along the side of it where it got pushed against the frame again instead of on the brake backing plate that wouldn’t cause rubbing. The tight constrain of the p-clipping also meant all the flex in the wires for suspension movement happened in about an inch of wire rather than along the length of the run like you’d see with a leaf sprung trailer, and the damage from that was obvious as well, again on three out of four corners. 
And the jank in the nice-looking wiring didn't end there. All the marker lights were T’d off a single run of wire down each side of the trailer, four on each side. Each splice in heat shrink. A couple of the lights were flickering, and the wires were loose inside the splice, so I cut open the heat shrink tube in both spots. The single run of wire was unbroken the whole length, with the splices made by carefully removing the insulation in the middle of the wire, and wrapping the marker light pigtail around the exposed spot. Very neatly done, and the heat shrink slid down the wire in advance of that indicates some serious advanced planning there by whoever wired the trailer. But in both cases, whoever went to the trouble of sliding pieces of heat shrink tube down a 16’ run of wire, very neatly stripping the middle of the wire and looming everything nicely with connectors no less, hadn’t actually done anything more to splice the wires than twist them together and heat shrink the “friction fit”. No crimps, no solder, just twisted together. Make it make sense. 
 

Something else unrelated that’a a bit of a peave of mine, if you absolutely must wrap something in electrical tape (my recommendation usually is don’t), start at the inner bit that’s hard to get to, and work your way out, finishing somewhere easy to reach, instead of going the other way. This ensures that if you have to go back in, you can just start at the easy to get to spot on the outside and peel the electrical tape back off, instead of having to either fumble around to get it started in the hard to reach spot, or else risk damaging wires by cutting the electrical tape off when you can’t pull it out from under itself.

Also, seam rippers work great for getting into tricky looms, much less risk to the wires than a knife of some kind. I don’t know that the one that comes in the Snap-on electrical pin tool kit is any different than something from a sewing store, either.

[AZJeff]

57 minutes ago, gogmorgo said:

 
 

Something else unrelated that’a a bit of a peave of mine, if you absolutely must wrap something in electrical tape (my recommendation usually is don’t), start at the inner bit that’s hard to get to, and work your way out, finishing somewhere easy to reach, instead of going the other way. This ensures that if you have to go back in, you can just start at the easy to get to spot on the outside and peel the electrical tape back off, instead of having to either fumble around to get it started in the hard to reach spot, or else risk damaging wires by cutting the electrical tape off when you can’t pull it out from under itself.

 

On the subject of electrical tape:  that vinyl stuff that is commonly found at hardware stores and auto parts stores is HORRIBLE for taping up wire looms.  The tape never stays wrapped at the end, and if the tape is used in a hot area (engine compartment), it gets all gooey, and is a mess to unwrap.

 

I found some stuff on Amazon made by Tesa in Germany that seems to be a cloth/vinyl matrix, and it stays put once wrapped, and does not get gooey if placed in hot areas.  And it’s really not expensive, either.