A Crash Course In Soldering and Modifying/Repairing Harnesses for Beginner Jeepers
ThisGuyUKnow
Full Time Jeeper
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- Harleysville, PA
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- 1986 CJ7 Laredo 4.0,Nv3550,D300 Twin Stick,AMC20 3.31, 31 BFG
Honda vtx1800c
** Before I get into this I just want to say that I know there are a wealth of experienced members that have plenty of experience with this subject. I do understand that there are other strategies and techniques and, well, more than one way to skin a cat. I hope this will just serve as a guide to our new members who might be just coming down with a case of the jeep thing**
We all have done it. Spent hours cursing and spitting on the name of our CJ's PO. Often we find modifications, repairs, and "upgrades" that leave us scratching our heads with sheer confusion.
One of the most common problems we face are botched repairs and extensions to the factory wiring harness. These repairs can be confusing and ,in some cases, dangerous.
To correct these wiring issues, we have to get our hands dirty by removing, splicing, replacing, extending, and repairing the wiring in our Jeeps.
For some this task is not too daunting, for others with Limited wiring experience maybe not so much.
In this post I hope to give you just a basic idea of how to safely and adequately make modifications to your jeep harness.
**The following information is mostly my opinions I have developed from working on wiring harnesses in my own personal projects. I am not a professional automotive electrician, however, I have done some very complex wiring modifications in both my Jeeps and my DD ('06 F150). Feel free to share your opinions if you are an experienced electrician or have other techniques that are easy for NOVICE wiring jobs, however; be respectful, this is not a thread intended to be an open debate.**
1. Forget Butt Connectors.
Maybe a little easier said than done. If possible you should avoid butt style connectors.
Why?
For starters, personal opinion, they are ugly.
Butt connectors create a mechanical connection between the two wires you wish to connect. This basically means that the electricity is flowing between two contacts and not through them. This allows air and corrosion to get in between. Think of when dragging your feet across the carpet and reaching for a door knob. The electricity arcs just before you fingers contact the metal and you should should see the arc. Similar concept to your spark plugs.
When using a butt connector, the gap may not be as dramatic as described above but there is still gaps in which corrosion, dust, oxidation, and just general things that do not help conduction to get in between these spaces.
There is a much better mechanical connection that I would suggest using in lieu of a butt connector, more on that later.
Also butt connectors rely on your crimp to be physically tight enough to minimize the gaps between the connection and, consequently, hold the wire in the butt connector. I have had plenty of experience with one side of a connector slipping off the wire with little to no pressure applied to it.
If you must use a butt connector, generally because the wire is too thick to heat up enough to accept solder, strip back any covering to expose the metal of the butt, crimp the wires and apply solder at either end of it then cover with electrical tape or shrink wrap. Or use a weather tight type butt connector and seal the ends to prevent corrosion from getting into the connector. This will, at a minimum, keep out some of the elements that cause corrosion in your mechanical connection.
2. Choose the correct size wire for the job
Ok, this is cause for quite a bit of debate on the forum world so bear with me. You have 3 forces your are worried about in an aging or repaired harness, voltage, OHMS (the measurement of resistance in a wire), and AMPerage. Most items in your vehicle will run at 12v, if you have an older jeep your system might be a 6v system. Amperage is what actually causes anything the requires power to function. (I am simplifying this as much as possible for more in depth explanations feel free to check out wiki or any other web source)
Different items draw different amounts of amperage, take a look at your fuse panel, each circuit has a specific amperage fuse. Whatever is labelled on the fuse is the max amperage a given circuit (CKT) can handle before the fuse will bust and need to be replaced. Usually this fuse is rated for a slightly higher amperage than the ckt it runs. For instance, the headlamp fuse may be 15a, this means that, for the factory lights used in this system, the headlamps pull less that 15a. If it did hit 15a the fuse would bust and the ckt would be forced open.
Too much resistance (measured as ohms) can cause wires to heat up. This can burn up the wire itself by causing it to heat up or pop the fuse in the ckt. This resistance can be caused by corrosion within the wire. The wires have braided copper strands that can get corrosion between them, resulting in resistance. Over time the rubber sleeve covering the wire can degrade,split, or stretch allowing the elements to get to the wire. Also botched splices with butt connectors or spade connectors can raise the resistance in a wire and cause issues. (Again this is a basic crash course in this subject for more technical explanations, feel free to do some further research)
When selecting the correct wire for the job, use the factory wire(if still available) as a guide. The manufacturer usually installs wire that is stronger than the ckt it runs. The larger a wire is the more amps it can withstand as well as resistance it can withstand before the wire disintegrates or burns up. The length of a wire is also a factor in in how many amps and how much resistance it can withstand. A length of wire that is 6 inches of a specific gauge can withstand considerably more than the same gauge wire at 6 feet. There are plenty of diagrams available online that will tell you how many amps a gauge of wire can withstand at given lengths.
So what does this mean with wire selection? It means that you do not want to use a smaller gauge that cannot withstand the amperage of whatever ckt you are putting it in. So do not use whatever wire you have laying around, especially if you are not sure what gauge the wire might be. On the other side of the token, if you have a ckt that only draws 10 amps, there is no reason to use 12ga or 10ga wire when a smaller gauge will do. Generally I try to use wire that is one to 2 gauges larger than what my circuit would need, I make sure that the fuse in the ckt will bust before the wire reaches the amperage it is rated for and the larger size of the wire will allow for some leeway as the wire ages due to engine heat or elements of the weather. Doing this keeps the bulkiness of your harness to a minimum and makes the wiring more manageable. If you were to use 10 or 12 ga wire for ckt your harness would quickly get so large you couldn't properly protect it with split loom conduit.
3. Strong Mechanical Connections
So, I mentioned earlier that there was another option to make a mechanical connection between two wires. This method is referred to as the Western Union Splice.
This is a very strong connection that was used to connect telegraph wires and cabling on suspension bridges in the old days. This is a very strong connection and, without, any solder will stand up to alot of pressure if done properly. Go grab some wire and try it! if done correctly you should not be able to pull the two wires apart without a lot of force. If you cannot solder or, do not want to try to solder (lazy!), making one of these connections and covering with shrink wrap (preferably) or electrical tap, will give you a much better connection than you can get with any butt style connector.
4. Soldering is Always the Best
Even the worst solder job will make a much better, longer lasting, and lower resistance connection than any mechanical connection.
To start, it is best to create a mechanical connection in the wires. Do not forget to put your shrink wrap on the wires prior to connecting them. (If i had a nickel for every time I have soldered a wire to find I forgot to put my shrink wrap on....) Personally, I like to start with my own modified version of the Western Union splice. I bend the two wires at a 90 degree angle. Using the actual Western Union Splice would also work here.
Then I interlock the two wires.
Finally, I twist the two wires together.
You want to make sure that all the loose strands are tight to the wire just like in the western union splice illistration above. It is good to keep a small pair of dikes around to clip off any access strands that might poke holes into you shrink wrap.
Now it is time to solder. This is prefereably done on a work bench where you can clamp the wire so it is parallel to the ground. If modifying a harness in your vehicle you will have to do your best to get the wire level. If it is leaning a particular direction, the solder will run and clump up on the lower end.
I prefer to use a soldering gun, available at most places that sell wiring goods, as it gets hotter. However, a regular soldering iron is generally enough for most gauge wires. The first thing you want to do is make sure the time of the iron/gun is clean. I'm very guilty of getting lazy and not taking the time to do this. You can clean it with a wire brush or brillo pad. You can also wipe off excess melted solder after soldering a wire with a wet sponge.
To start you want to start with the iron/gun under the under the wires and you want to get it hot enough to melt a dab of solder onto the tip and touch it to the bottom of the wires. This dab of solder will conduct the heat of iron into the wires. Your goal is to get the iron/gun hot enough to not completely burn off the solder and to get the wire hot enough to draw the solder into the strands.
Once you got a good dab on the iron/gun you want to take excess solder and hold it to the top of the wire opposite of the dab. When the wire heats up to the proper temperature it will get hot enough to melt the solder touching the wire at the top and this process will draw your dab of solder into the wire towards the top. Clear as mud? You may have to alternate between the top and the bottom on where you iron/gun is to keep feeding it solder.
When finished you should have a fairly consistent coating of solder connecting your two wires into physically one wire. This will greatly reduce any resistance do to aging wires or poor mechanical connections. As you can see above, although I tried to get the wire as even as possible it was still angled toward the front of the vehicle and most of the solder settled on that low side.
Once you have a good solder cover the wires in shrink wrap and you should have a very clean durable splice, repair , or extension that will last a long time without causing your trouble later on.
The important thing to remember when Soldering is to get the wire, or metal connector to the wire hot enough to draw in the solder. This is similar in concept to sweating a copper pipe.
When trying to solder heavier wire 12ga to 10ga or larger, this method is very hard to do right because the wire is too bulky. I do not have a set method I use to solder these types of wires, it just depends on what I can get to work.
Hopefully these basic information is useful to some of you out there afraid or inexperienced with modifying/repairing your factory wiring. The method for soldering I listed above can give you a place to start. With some practice and some confidence you may find a better/easier way to solder or splice wires into your vehicle, there is more than one way to skin a cat and there are plenty of methods for soldering wires in your automotive application.
We all have done it. Spent hours cursing and spitting on the name of our CJ's PO. Often we find modifications, repairs, and "upgrades" that leave us scratching our heads with sheer confusion.
One of the most common problems we face are botched repairs and extensions to the factory wiring harness. These repairs can be confusing and ,in some cases, dangerous.
To correct these wiring issues, we have to get our hands dirty by removing, splicing, replacing, extending, and repairing the wiring in our Jeeps.
For some this task is not too daunting, for others with Limited wiring experience maybe not so much.
In this post I hope to give you just a basic idea of how to safely and adequately make modifications to your jeep harness.
**The following information is mostly my opinions I have developed from working on wiring harnesses in my own personal projects. I am not a professional automotive electrician, however, I have done some very complex wiring modifications in both my Jeeps and my DD ('06 F150). Feel free to share your opinions if you are an experienced electrician or have other techniques that are easy for NOVICE wiring jobs, however; be respectful, this is not a thread intended to be an open debate.**
1. Forget Butt Connectors.
Maybe a little easier said than done. If possible you should avoid butt style connectors.
Why?
For starters, personal opinion, they are ugly.
Butt connectors create a mechanical connection between the two wires you wish to connect. This basically means that the electricity is flowing between two contacts and not through them. This allows air and corrosion to get in between. Think of when dragging your feet across the carpet and reaching for a door knob. The electricity arcs just before you fingers contact the metal and you should should see the arc. Similar concept to your spark plugs.
When using a butt connector, the gap may not be as dramatic as described above but there is still gaps in which corrosion, dust, oxidation, and just general things that do not help conduction to get in between these spaces.
There is a much better mechanical connection that I would suggest using in lieu of a butt connector, more on that later.
Also butt connectors rely on your crimp to be physically tight enough to minimize the gaps between the connection and, consequently, hold the wire in the butt connector. I have had plenty of experience with one side of a connector slipping off the wire with little to no pressure applied to it.
If you must use a butt connector, generally because the wire is too thick to heat up enough to accept solder, strip back any covering to expose the metal of the butt, crimp the wires and apply solder at either end of it then cover with electrical tape or shrink wrap. Or use a weather tight type butt connector and seal the ends to prevent corrosion from getting into the connector. This will, at a minimum, keep out some of the elements that cause corrosion in your mechanical connection.
2. Choose the correct size wire for the job
Ok, this is cause for quite a bit of debate on the forum world so bear with me. You have 3 forces your are worried about in an aging or repaired harness, voltage, OHMS (the measurement of resistance in a wire), and AMPerage. Most items in your vehicle will run at 12v, if you have an older jeep your system might be a 6v system. Amperage is what actually causes anything the requires power to function. (I am simplifying this as much as possible for more in depth explanations feel free to check out wiki or any other web source)
Different items draw different amounts of amperage, take a look at your fuse panel, each circuit has a specific amperage fuse. Whatever is labelled on the fuse is the max amperage a given circuit (CKT) can handle before the fuse will bust and need to be replaced. Usually this fuse is rated for a slightly higher amperage than the ckt it runs. For instance, the headlamp fuse may be 15a, this means that, for the factory lights used in this system, the headlamps pull less that 15a. If it did hit 15a the fuse would bust and the ckt would be forced open.
Too much resistance (measured as ohms) can cause wires to heat up. This can burn up the wire itself by causing it to heat up or pop the fuse in the ckt. This resistance can be caused by corrosion within the wire. The wires have braided copper strands that can get corrosion between them, resulting in resistance. Over time the rubber sleeve covering the wire can degrade,split, or stretch allowing the elements to get to the wire. Also botched splices with butt connectors or spade connectors can raise the resistance in a wire and cause issues. (Again this is a basic crash course in this subject for more technical explanations, feel free to do some further research)
When selecting the correct wire for the job, use the factory wire(if still available) as a guide. The manufacturer usually installs wire that is stronger than the ckt it runs. The larger a wire is the more amps it can withstand as well as resistance it can withstand before the wire disintegrates or burns up. The length of a wire is also a factor in in how many amps and how much resistance it can withstand. A length of wire that is 6 inches of a specific gauge can withstand considerably more than the same gauge wire at 6 feet. There are plenty of diagrams available online that will tell you how many amps a gauge of wire can withstand at given lengths.
So what does this mean with wire selection? It means that you do not want to use a smaller gauge that cannot withstand the amperage of whatever ckt you are putting it in. So do not use whatever wire you have laying around, especially if you are not sure what gauge the wire might be. On the other side of the token, if you have a ckt that only draws 10 amps, there is no reason to use 12ga or 10ga wire when a smaller gauge will do. Generally I try to use wire that is one to 2 gauges larger than what my circuit would need, I make sure that the fuse in the ckt will bust before the wire reaches the amperage it is rated for and the larger size of the wire will allow for some leeway as the wire ages due to engine heat or elements of the weather. Doing this keeps the bulkiness of your harness to a minimum and makes the wiring more manageable. If you were to use 10 or 12 ga wire for ckt your harness would quickly get so large you couldn't properly protect it with split loom conduit.
3. Strong Mechanical Connections
So, I mentioned earlier that there was another option to make a mechanical connection between two wires. This method is referred to as the Western Union Splice.
This is a very strong connection that was used to connect telegraph wires and cabling on suspension bridges in the old days. This is a very strong connection and, without, any solder will stand up to alot of pressure if done properly. Go grab some wire and try it! if done correctly you should not be able to pull the two wires apart without a lot of force. If you cannot solder or, do not want to try to solder (lazy!), making one of these connections and covering with shrink wrap (preferably) or electrical tap, will give you a much better connection than you can get with any butt style connector.
4. Soldering is Always the Best
Even the worst solder job will make a much better, longer lasting, and lower resistance connection than any mechanical connection.
To start, it is best to create a mechanical connection in the wires. Do not forget to put your shrink wrap on the wires prior to connecting them. (If i had a nickel for every time I have soldered a wire to find I forgot to put my shrink wrap on....) Personally, I like to start with my own modified version of the Western Union splice. I bend the two wires at a 90 degree angle. Using the actual Western Union Splice would also work here.
Then I interlock the two wires.
Finally, I twist the two wires together.
You want to make sure that all the loose strands are tight to the wire just like in the western union splice illistration above. It is good to keep a small pair of dikes around to clip off any access strands that might poke holes into you shrink wrap.
Now it is time to solder. This is prefereably done on a work bench where you can clamp the wire so it is parallel to the ground. If modifying a harness in your vehicle you will have to do your best to get the wire level. If it is leaning a particular direction, the solder will run and clump up on the lower end.
I prefer to use a soldering gun, available at most places that sell wiring goods, as it gets hotter. However, a regular soldering iron is generally enough for most gauge wires. The first thing you want to do is make sure the time of the iron/gun is clean. I'm very guilty of getting lazy and not taking the time to do this. You can clean it with a wire brush or brillo pad. You can also wipe off excess melted solder after soldering a wire with a wet sponge.
To start you want to start with the iron/gun under the under the wires and you want to get it hot enough to melt a dab of solder onto the tip and touch it to the bottom of the wires. This dab of solder will conduct the heat of iron into the wires. Your goal is to get the iron/gun hot enough to not completely burn off the solder and to get the wire hot enough to draw the solder into the strands.
Once you got a good dab on the iron/gun you want to take excess solder and hold it to the top of the wire opposite of the dab. When the wire heats up to the proper temperature it will get hot enough to melt the solder touching the wire at the top and this process will draw your dab of solder into the wire towards the top. Clear as mud? You may have to alternate between the top and the bottom on where you iron/gun is to keep feeding it solder.
When finished you should have a fairly consistent coating of solder connecting your two wires into physically one wire. This will greatly reduce any resistance do to aging wires or poor mechanical connections. As you can see above, although I tried to get the wire as even as possible it was still angled toward the front of the vehicle and most of the solder settled on that low side.
Once you have a good solder cover the wires in shrink wrap and you should have a very clean durable splice, repair , or extension that will last a long time without causing your trouble later on.
The important thing to remember when Soldering is to get the wire, or metal connector to the wire hot enough to draw in the solder. This is similar in concept to sweating a copper pipe.
When trying to solder heavier wire 12ga to 10ga or larger, this method is very hard to do right because the wire is too bulky. I do not have a set method I use to solder these types of wires, it just depends on what I can get to work.
Hopefully these basic information is useful to some of you out there afraid or inexperienced with modifying/repairing your factory wiring. The method for soldering I listed above can give you a place to start. With some practice and some confidence you may find a better/easier way to solder or splice wires into your vehicle, there is more than one way to skin a cat and there are plenty of methods for soldering wires in your automotive application.
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