Thread: Wiring Harness Terminations

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What approach do you use, cut to length and final terminate wire by wire as you go; or temporary terminations to verify operation, then go back and cut to length? Seems that leaving the wires long is going to be a mess and waste a bunch of terminations, but it may be a necessary step? For example, with my fuse block location (up high behind dash, driver's side) my conductors to the steering column plug need to be shortened about 6" to 10" to be neat - my temptation is to cut them wire-by-wire, staggering butt connectors to eliminate bulk now vs getting it all wired and going back to do this later. Same in the trunk - about 8' of extra conductor on each circuit that is going to have to be cut out at some point.

Rog, I get mine routed to where they will eventually be connected, mark them with a piece of masking tape, then when all the wires are in position I start making connections...I do this one circuit at a time.

Originally Posted by Dave Severson

Rog, I get mine routed to where they will eventually be connected, mark them with a piece of masking tape, then when all the wires are in position I start making connections...I do this one circuit at a time.

Dave,
When you say one circuit at a time do you mean you get the wires run to the trunk, mark each wire for lights, fuel tank level, 3rd brake, etc, and then terminate circuit by circuit before moving to say the front circuits? If the answer to that is 'Yes', then do you already have the light switch powered up to check those circuits or can that wait until the dash wiring is all done?

Trying to get a handle on how much "temporary" terminating and hot testing I need to be doing...

I start by laying the harness out and grouping the circuits together such as dash,rear of car,engine bay,etc. I'll then take a few small wire ties to hold each group together. Decide where to mount the fuse box and then start laying out your groups to where they go,planing the routing & mounting as you go. Once you get your groups in their general locations I like to wrap each group with good quality electrical tape sorta like an OEM harness,but leaving plenty of wire out the ends as you can finish wraping later. I like to start at the dash and column first,one circuit at a time, cutting to length, and connecting permanantley using solder and heat shrink,"never ever use crimp connecters"
Main thing is you don't want any dangling wires or extra wire that you have to roll up,everything should be nice and neat and as short as possible. You may very well have some extra circuits that will not be used at this time such as map lights,air conditioner,etc, with those its a good idea to roll them up and hide them behind a kick panel or such in case you want to use them at a later time. Don't forget about grounds, on a steel car you'll need battery to engine,engine to chassis,engine to body. On a glass car you'll need battery to engine,engine to chassis,and every componet mounted to fiberglass will reguire a ground to engine or chassis. Hope this helps ya. Just take your time and plan it out,you'll do fine.

Roger, I don't do any circuit testing or temporary hook ups for testing. Most of those kits are pretty good quality and your gonna eat enough time up as it is.

Originally Posted by HWORRELL

Roger, I don't do any circuit testing or temporary hook ups for testing. Most of those kits are pretty good quality and your gonna eat enough time up as it is.

Thanks. The biggest hurdle for me was deciding on the fuse block location and welding in the plate for it, knowing that it was a commitment that would be difficult to impossible to change. My EZ Wire harness came with general groupings by area, but those must of course be adjusted for the specific vehicle layout. I was at that point this morning and found that the wires for the rear area seem to be long enough for a Caddy Limo. That got me thinking about temporary connections, and I was seeing this wiring project going into December I'll start cutting & terminating, area by area.

Roger - what type of wiring system do you have? If it is already permanently terminated at the fuse block, then you probably should do a full layout before you do the final terminations at the powered device. I'm not real fond of them as sometimes it's a real PITA to make a run with all of those extraneous wires and the fact that sometime it is just plain easier to feed a wire the other direction or change a route. Since my block was behind the seat, it had other considerations, but mostly how to route the wires without being able to see them - I would do it different another time - but, it's done, everything works...... I did one system at a time, checking continuity with each by my powered tester/light. I then after getting a system in, turned on the master switch to check that entire system just to make sure. I used lots of masking tape as Dave S suggested and several hundred cable ties doing, redoing and re-redoing ad nauseum.



One rerouting shown above (i.e. re - re - re - redoing)

I am just going through this right now, installing a Rebel 9 + 3 set up in my 27. I spent one night just sorting through the harness and eliminating what wires my car didn't need, like radio, a/c, heater, and third brake light. Then I coiled up the remaining wires and marked them with masking tape as to their purpose (ie, rt frt turn signal, etc)

After that was done I decided on where the fuse block would go. Dan talked me into making a hinged panel to mount it, like he did, and I am glad that I took his suggestion. The underdash area in a 27 is very limited and having it swing down is making it easier and gets it out of the way while running wires.

Once it was mounted I started by running the main 10 gauge red wire back to the starter solenoid so that I had power to the block. Then I ran the wires to the ignition switch so it was live. As I continued to run wires I would temporarily wire tie them into the bundle, using 4 inch wire ties. These are cheap and are going to be cut off as I run more and more wires into that same harness, but they keep things organized as I work.

So to answer your original question, yes, I run one wire at a time, cut it to the correct length, and then terminate it with the correct end. I am also using Painless plugs in line this time so that I can unplug the wires in the event I ever have to remove the body, rather than having to cut or unscrew the wires at their ends.

Don

Originally Posted by IC2

Roger - what type of wiring system do you have? If it is already permanently terminated at the fuse block, then you probably should do a full layout before you do the final terminations at the powered device. I'm not real fond of them as sometimes it's a real PITA to make a run with all of those extraneous wires and the fact that sometime it is just plain easier to feed a wire the other direction or change a route. Since my block was behind the seat, it had other considerations, but mostly how to route the wires without being able to see them - I would do it different another time - but, it's done, everything works...... I did one system at a time, checking continuity with each by my powered tester/light. I then after getting a system in, turned on the master switch to check that entire system just to make sure. I used lots of masking tape as Dave S suggested and several hundred cable ties doing, redoing and re-redoing ad nauseum.
One rerouting shown above (i.e. re - re - re - redoing)

Dave W,
E-Z Wiring, 21 circuit pre-terminated fuse block. I have the fuse block mounted up high behind the dash, driver's side which I may regret in the future, but it is done and it eliminates a large number of wires on the floor. With the EFI ECU I have several fuse block circuits that will not be used, or which can be used for other purposes in the future, like the dedicated fuel pump fuse/wire - my pump is wired direct from the engine harness, controlled by the ECU. I also have circuits for power locks and power antenna that I don't have and likely will never have. Like HWorrell suggests, I will cut those a bit shorter and coil them for future use rather than cut them close to the block as suggested by E-Z Wire.

Run your wires and use bread loaf twisties or a insulated solid #16 gauge wire to temporarily hold your wires until you are ready for final tie with tie wraps. Saves you accidently damaging any wires trying to cut off tie wraps in the process. If you don't have a good crimp tool then go buy one and throw away that POS multi tool you have which will only cause you trouble later with bad connections. As for as the comment about using crimp connectors there is absolutely nothing wrong with using crimp connectors if you have the proper tools to do them with. I would not solder my connections as the heat will weaken the wire strands. Each to his own. I will say do not use cheap connectors on your car from home depot or local hardware store. Go to electrical supply house and ask for T&B or Panduit connectors along with some heatshrink tube for each connection. Take your time and watch for any edges that may chaffe your wire. Leave a few inches of slack for each connection with no undue stress applied on the connection. Remember every extra connection is only a place for something to wrong so avoid unnecessary splices and such. Good luck.

Buzz is right..........crimp terminals are perfectly fine, and in some cases much better than soldered ones. Soldering can make the ends brittle and prone to breaking. I know there will be an argument on that, but if you feel comfortable soldering, do it, and if you like crimping, go that route. We crimp everything.

Don

I agree with Buzz. There are a few places where I will solder wires in a car harness, but not very many. I mounted my fuse block under the dash with a large velcro strip. That way, I could pull it down to work on it. I had a Ron Francis kit, so the layout was something different, but I started at the fuse block, laid everything out and temporarily tied bundles together with wire ties.

I left the entire length of wire lying by each terminus until I knew where everything went. Then, I did groups. Main power from battery to fuse block then ignition switch and engine wiring, including the fuel pump. Lights next, then other accessories, then the behind the dash wiring. I have a terminal board on the back of the dash so I can remove everything as a unit.

I left wire ties on the bundles under the dash and in the trunk. Where I had to run the wires along the floor (near the sill or the trans hump), I cut the ties, made the bundle flat, and secured them with the same aluminum tape I used to seal the joints on the floor sound deadener/insulation. Somewhere on the site, there are some photos of most of this, but I lost my pictures in a computer crash.

You're a logical guy, Roger. Think it through, and you'll be fine. Although, there were a couple of times I had to say . . . "Darn. I cut it off twice, and it's still too short."

Originally Posted by rspears

Dave,
When you say one circuit at a time do you mean you get the wires run to the trunk, mark each wire for lights, fuel tank level, 3rd brake, etc, and then terminate circuit by circuit before moving to say the front circuits? If the answer to that is 'Yes', then do you already have the light switch powered up to check those circuits or can that wait until the dash wiring is all done?

Trying to get a handle on how much "temporary" terminating and hot testing I need to be doing...

I wait until I get all the wires permanently routed and connected, then pull all the fuses, and plug them in one at a time and check each circuit as I go... I don't bother with temporary hookups to check things. Not a bad idea to test as you go I guess, I do enough wiring and usually use the same brand of harness and accessories that it's no big deal anymore...however this Plymouth with all the electronics, EFI, etc is going to take me a bit longer. Anything I'm in doubt about I draw the circuit out on paper first, study it for a bit then wire it up.

Another thing I do to keep the frustration level down is to not sit and do all the wiring at one time...I'll do a bit of wiring, then some block sanding or whatever, back to the wiring for awhile and keep going that way.. I like to take my time and think things through rather then battling through a task that presents a few challenges---then redoing it all later. If you don't keep it all fun, building a Hot Rod can just become another job....

If CRS doesn't take over I'll photograph some of what and how I did mine paper wise and post in the morning - it's a full 1" loose leaf note book.

Originally Posted by Henry Rifle

You're a logical guy, Roger. Think it through, and you'll be fine. Although, there were a couple of times I had to say . . . "Darn. I cut it off twice, and it's still too short."

Yeah, I spent an hour or so this morning going through the harness and segregating out several circuits that I won't have, and shifting a few others to the right areas for my build. I was just a bit overwhelmed with it all. I got the rear of the car wired later today after having to make a parts run, minus only the fuel sender which is a quick ring lug and maybe a ground wire but I think it is OK (wife got home and was ready to go to dinner, so work halted for now...)
I am using the approach recommended by E-Z Wire, which is to run all circuits final, hook up the positive battery cable, then with everything "off", doors closed, etc, run a voltage check between the negative cable and the negative post (ammeter or test light) - if all is good it should be zero/near zero or a very dim test light (radio memory, EFI memory, etc). If the test light is bright there is something mis-wired.