This page explains how to reuse plastic wiring plugs by extracting the metal connectors, connecting the new wires to the old metal connectors, and putting it all back together again. This is important if you are doing some re-wiring work in an existing vehicle - splicing wires together in the middle of a wiring harness is messy and generates extra heat in the harness. You want to use a single wire between each connector when ever possible - and the tricks explained here can help you do that.

Eventually I'll add more pictures to this. For now, the only pictures I could fine that applied here were from the Ron Francis' Wire Works online catalog. (If you need new connectors, contacts, or other wiring aids, you should buy them there.) I tried to photograph some of the connectors and contacts I've bought from Ron Francis, but my camera refuses to focus up-close enough to show the details that I wanted to show.

First, the warnings and cautions. You're going to be working with old and possibly brittle plastic connectors that will likely be dirty, grimy, and hard to see clearly. They'll probably be attached to the car in a hard to get to and/or hard to see location. You're going to be removing pieces that are designed to go in and not come out on their own ever again. If you mangle stuff, you're in big trouble because replacements parts for the plastic parts of the connectors are not easy to come by for most cars. I have been told than some of the more interesting and hard to find connectors on GM vehicles (such as the main firewall connector behind the fuseblock) are available through International Harvester/Navistar - they use the same parts on their vehicles and they sell everything individually.

Now, the good news. If you do this right, no one will be able to tell what you did - at least not easily. It looks factory and most importantly works like the factory intended for many years to come. The appearance of exposed wiring (such as in the engine compartment) is a critical thing in how nice your engine looks when you open the hood, and the techniques here are one way to achieve a nice look. If you want to go for the "sleeper" stealth look, then this is your ticket. If you want to just do a clean job without cutting and hacking, this the set of how-to instructions for you.

Overview and Terminology

Each wiring connector on your car is made up of two plastic pieces (the housings) - one male and one female. Inside those housings are one or more metal contacts (usually brass) that the housing orients so that they will touch the proper contact on the other half of the housing but not anything else. The internal metal contacts also have male and female pieces. The male housing usually contains female contacts - this is so the housing can properly enclose the contacts to reduce the chance of one of them shorting out. The housing is designed to ensure the connector stays together and all of the contacts touch each other so they will conduct electricity - even after 50 years or more, they should still be doing their job.

The basic idea here is to disconnect the two halves of the connector and then remove the desired contact from one (or both, if needed) of the housings. You can then remove the existing wire and attach whatever length and color of wire that you need to the contact (or to a new contact if you can find the right style) and put it back into the housing in the original location. Once you put the new wire inside the existing wiring harness and plug the connector back together, the change is almost invisible and just as functional as if it was done at the factory. The only hint is that the new wire will be cleaner than the original ones, but a few months time usually takes care of that problem too. :-)

Contact Retention Methods

There are separate procedures for removing male and female contacts because they tend to differ in the ways they are retained in the housing. This is very important to understand - this is the tricky part of the entire process and this is where you will usually screw something up. Take your time and do it right - mangling the housing by acting like a gorilla won't help you much. The forces involved here are very small - think delicately. If you have to force it, you're probably not doing it right - stop and double check yourself.

The common details are that these contacts are designed to be connected to the wire (via soldering, crimping, or both) and then inserted into the housing from the back. You will be accessing the contacts from the front of the housing (the part the faces the other half of the connector when it's fully assembled) to attempt to "un-clip" them and slide them out the back of the housing. The contacts are designed to resist the force of the two halves of the housing being clipped together (this tends to force the contacts towards the back of the housing) as well as the force of the connector being pulled apart (this tends to pull them out the front of the housing.) You are just seeking to reverse the installation procedure by gently holding open whatever clip holds the contact in place while gently pulling the wire and contact assembly out the back of the housing. Once it starts coming out, the rest is easy - it's the first 1/8" or so that's the hard part.

Removing Male Contacts

The male contact is usually a flat "blade" about 1/4" wide. It has a slot cut in it from the back (towards where the wire hooks to it) running almost all the way out to the tip. At the base of the blade there are tiny projections that stick out about 1/16" and hold the contact in the housing. There are tiny depressions in the housing that these projections clip into and prevent the contact from moving forwards or backwards in the housing. That slot acts like a spring - when the contact is inserted into the housing, the slot closes just enough to allow those projections to slide into the housing - as soon as those projections hit the depressions in the house, the slot expands back to normal size and the contact is held in place. Look at the picture above to get an idea of what I'm talking about. When you look at the housing with the male contacts in it, this is all very easy to see and access before you remove the contacts. Compared to the female contacts, the easy visual and physical access to the male contacts usually makes them much easier to remove.

What you need to to is use a pair of small pliers to gently squeeze the contact from the sides and close the slot enough to that those projections will move out of the depressions in the housing and allow the contact to slide back. You must also take care to center the contact in the housing as you attempt to remove it - if you "close the slot" to make the contact thin enough to slide out, but you still force one of the projections into it's matching depression - the contact will not come out of the housing. Close the slot with gentle pressure and wiggle the contact out slowly - once it comes free it will slide the rest of the way out easily. Even though this sounds obvious, make sure that your pliers are not pressing against the front of the housing as you attempt to remove the contact. You're working with very close tolerances here.

Removing Female Contacts

The female contact is a bit more complicated. It has to wrap around the male contact, guide it into place, and provide some sort of "spring" to ensure they always touch each other - all without making the connector overly hard to connect and disconnect. The way it does this is by being a "u" shaped (if you look at it from the "front" end of the housing) to wrap around the male terminal and a folded over front edge to help guide it into place. It also has a small piece of it's main section bent up slightly to force the male connector to ride against the inside surfaces of the "u" shape and keep a good contact. This entire assembly must be retained in the housing against the same pushing and pulling forces the male contact has to contend with. It does this with two separate systems - one for the push and one for the pull. (Luckily, we only need to worry about the push system for removing the contact.) Since it has more surface area (when viewed from the front of the housing) the "pull" force is handled by having the hole in the front of the housing be slightly smaller than the contact is so that it cannot slide out the front of the housing. The "push" force is handled by a small piece of the connector that is bent out at a slight angle to act as a spring. When the contact is pushed into the housing, this projection will pass over a small raised area or over a small depression in the inside of the housing. It will them push outward into the depression such that the "end" the the metal spring piece is now too wide to allow it to move back out of the housing. You can't see it in the picture above because it's on the "bottom" of the contact and the widest part would be towards the back of the contact where the wire attaches to it.

What you need to do is figure out where that small projection/spring is at, and gently force it towards the main body of the contact while we push the contact out the back of the connector. To do this you should use a small jeweler's screwdriver (the kind you use to tighten screws on eyeglasses and such) or a small set of dental-style tools. You will need to insert your very thin, small tool into the housing from the front, slide it down along the contact, find the small projection/spring, and gently force it towards the contact while you pull the entire contact and wire assembly out of the back of the housing. It's a bit tricky, but if you take your time you will find the right place and it will come right out. Be especially careful of forcing these out - it's very tempting to put a lot of force on the plastic housing by using the small tool as a pry-bar. Don't do this! Be gentle and don't force it. The housing can be permanently distorted - or worse yet crack and break - very easily.

Removing Old Wires From Old Contacts

This is really tricky part - if you need to re-use the old contact you just removed, you will need to remove the existing wire from it. If at all possible, get new contacts from someplace like Ron Francis' Wire Works and use them instead. Save the old wiring in case you ever want to return the vehicle to it's original condition. As an example, I think the male contacts are item FM-8. They're cheap and easy to order. Use your existing contacts as a comparison to make sure any new contacts you buy are going to work properly.

Your contacts may have wire crimped or soldered on - maybe both. (If it's soldered, you're getting pretty desperate to try and save the contacts, but it can be done...) If present, you need to remove any solder first by heating the joint with a soldering iron and using a "solder sucker" to remove as much solder as you can. If it's not crimped, the wire will fall off at this point and you can move on to connecting a new wire to it. If it is crimped, you will need to un-crimp the joint as detailed below while applying heat to the joint with a soldering iron. Unless your luckier or better than I am, you can count on burning your fingers a bit on this one. (No pain, no gain?)

To un-crimp a joint, you just need to carefully bend back the metal pieces that were crimped over the wire. Be careful not to over-stress or break them as you will need them to crimp a new wire to the contact later on. Use a small jeweler's screwdriver or "dental pick" type of tool to get things started and work from there. Once the wire is loose, you can pull it out and gain some more working room to pry the metal crimp open far enough to put a new wire in it.

Connecting New Wire to Your Contacts

This is the easy part. Just insert the new wire and crimp the connection down. If the contact has an extra set of crimp "fingers" to grab the wire back by the insulation, don't forget to crimp them down too. Use a quality "W" crimping tool instead of the simple "oval" ones if at all possible - they make a much better connection. (The "W" crimp tool has a small projection on one side joint to force the wire inside the joint to make better a better connection with the contact. Always put that pointed side of the tool away from the "open" side of the contact when you crimp it down.)

If your contact doesn't have any way to crimp a wire onto it, or you want to be really sure it stays connected, you can carefully solder the wire to the contact. Soldering is easy to learn but takes a while to master, but the nice part is that it's hard to really screw things up so bad that they can't be used - or at least salvaged. Your local Radio Shack is a great source for all kinds of soldering supplies if you need to get some.

You may need to wrap a small piece of electrical tape around the crimped/soldered end of the contact so that no exposed wire or metal sticks out past the back of the housing once it's all assembled again. If so, now is the time to do it. Don't go nuts with the tape - a single layer of tape will do just fine. If you use too much, the contact and wire assembly may not fit into the housing properly because it's too large.

Putting it all Back Together Again

This is the no-brainer part of things. You take your freshly connected contact and new wire assembly and push the contact into the back of the proper slot on the housing until it "clicks" into place. The male contacts are usually not directional - just match any other contacts already in the housing. The female contacts are usually directional - the only fit properly one way. Either match the other contacts in the housing already, or look very closely inside the housing to figure out which way it goes.

After you get all of your new contacts installed in the housing, you should test-assemble the two housing pieces to be sure they fit properly - the new contacts may need to be wiggled around a bit to get everything to go together properly. Again, be gentle and take your time. The connector should slide together pretty easily. Once it's together, you can put your new wire into your harness as you see fit. The connector is ready to be assembled and put back where it belongs and you can concentrate on the rest of your wiring efforts.

Comments? Kudos? Got some parts you'd like to buy/sell/barter/swap? Nasty comments about my web page so far? You can email Mike or Debbie.

Page last updated 04/26/2008 11:41:08 PM