New wire harness install


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Sep 25, 2022
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Cannot tell you about the pucker factor when installing a hew harness, with ignition switch, where OEM was having problems, and turn signal switch. The light switch seemed OK. So, remove the old harness, a mess, for sure. Then, lay out the new harness on the floor and try to negotiate what needs to be done. The PL harness has been good so far. So, place the new one in the dash, and try to find a place for the new fuse panel, that must be able to be accessed easily. Pull the engine and headlight harness thru the dash....I used the existing bulkhead fitting for a new hole. So, began with Ign switch, then light switch, and wiper switch. Then focus on the wires in the engine bay for starter relay, alternator, coil, and sensors, incl new OP pressure gauge. So, now need to test the harness using a 10-15 amp fuse for power, and turn on switch, check those things that should have ign power. Then, turn on light switch and check both front and rear lights (harness output). Also, in the mix, is to power up the OEM harness for both front and rear lights to see if the existing harness works, to use it for now. Lights all work...or mostly. Harness OK for now. So, after checking the harness by turning on the ign switch, then light switch and looking for output at the harness, found a couple problems that had to be attended to. So, next was new turn signal and horn relay, with output at the rear turn signal and brake lights. So far so good...after a month of work, I am a happy camper.
I wish ME was a WE for some help and ideas, when I cant think. But, I will post a couple thoughts along the way on this, just for others who are doing similar later. No biggie, but have already written many notes to mfr about issues I found. And, for sure, one thing for wiring folks to consider is the mfr of the terminals. I got some initially that were china, and do not like them mainly due to weight. A bit flimsy which includes the locking tab and ability to hold shape in a connector. One of the big things people need to remember is that the harness folks have found a better way to handle some things that the OEM did. For instance, there are several places that OEM took power for a circuit, say on a brake light switch, or off of the wiper switch, that the new guys simply added a new wire to connect to. But, you have to be thinking about this as you go thru the circuits. Also, another biggie, is that when you remove the old harness, do a LOT of prep work first, to ID branches, locations, connectors, with notes and pics. This will help ID problem wires when going back. I have gone back several times to the OEM harness to take things apart to ID wire colors, routes, etc that you will need to do, so SAVE everything as you dismantle. I want to add some other things later to think about, and also a test regimen as you get thru the initial install, but before you begin to attach any loads. Test the harness first, then the car circuits, and use low amp fuse for early test work....but more on that later.
What is PL harness?

For myself, I would have individually rung out each wire, identifying and marking each prior to any removal.

My suspicion is that 90%+ of the factory harness is good.
Good luck and however you proceed, pay horrific attention to detail and document everything!
I know some sites dont like ref to mfrs, but I will say painless and let it go at that. Also, this OEM harness has been shankered for its whole life, including with home wiring nuts all over, bare wires wrapped around each other, many areas that actually caught fire and are down to burned strands of copper, and much more, so there was no fixing this mess. I am saving and using some for now, but will take some time to replace more, like the headlite array, later. I did not want to remove the interior, and thankfully, the tail wiring from the dash is working....except for more burned wires.....for dome lights, in the console area. None of the console wires are liking to be Ohmed, and some great mech screwed up the reverse light switch in the shifter. So, after lifting the console cover, I am again wishing for that WE mentioned above, for help.
What is PL harness?

For myself, I would have individually rung out each wire, identifying and marking each prior to any removal.

My suspicion is that 90%+ of the factory harness is good.
Good luck and however you proceed, pay horrific attention to detail and document everything!
Maybe painless wiring?
This car, sold the year I finished HS, is going to make me crazy. So yes, I bought roadkill, that I had hoped to just bring along to drive.....hmmm. So, a friend has been after me to use the new wiring to crank it up. So, finally the other day, I did so. Had to finagle with the neutral safety switch....seemed to work in N but not P, but finally did want to crank. So, after flushing out the bad gas some time ago, rebuilding the carb, and other things, it fires up, with a taste of dumped fuel down his throat. Runs fine at speed, and NOW does not really want to idle. Hmmm, maybe trash in the filter yet. Did idle fine after carb rebuild to get her running before all of this nitemare with wires. And, on top of that, the power steering pump started puking oil, which it had not been doing. One step forward, two steps back. I am going back to bed and pull covers.
More days of testing, and I want to note that the comment above by 317 is not far off, regarding the OEM harness. I have found that the headlight and tail light harness portions are fine.....those not screwed with by shop monkeys. Also, just went thru the small harness in my console with three lights and BU switch, all good after a bit of cleaning....very happy about that. Also have found my yellow light switch leg actually works with the door switch.....ah hah, something good. So, your comment is supported by these findings where someone did not use bad judgement in adding wires with poor connectors, resulting in several "fires" as I have found them. Much of this was found in the major harness near the fuse box, after which I just exhaled. Interesting to find some good stuff, at this age. One thing I am going to speculate on is that the dodge boys and mr chrysler did not do well on the bulkhead connectors.....they prob worked OK for the normal life of the car.....but mine obviously caused much of the bypassing done with about six major wires thru the firewall that were added into the mess above. Also, I found huge corrosion in the connector pins as I removed it....too bad. My connector was also distorted a bit, and had some bad terminal ports. Doubt that it could have been saved....who knows. However, I cannot even imagine anyone trying to rewire the bulkhead connector, but who knows what folks can do. However, again, kind of agree with the above comment, with some exceptions for my roadkill. Sorry to be so wordy
Couple quick updates on harness install. I am really liking the painless wire loom. Not easy to wrap over existing wire, so I try to feed wires thru when I can, but is much better than the cheap fabric weave stuff, and I have never liked the plastic loom material....functional maybe. But, as I begin to install the harness to the OEM tail harness, I have done my testing on both the harness output, and also have powered up the car tail to the lights. Biggest issue on this is how to store any excess loop under the dash where the two systems connect. I am thinking of wrapping and putting into a cloth bag, like a checkbook zipper bag, just to hide and protect this excess. I wanted excess in case of future changes, AND it would have been tough to put on connectors and shrink tubing under the dash, if left short and tight. Also, if you are doing this, dont forget to add pigtails from the dash panel light wire, that will extend across the dash for all the panel lighting, and dont forget new gauges. One more thing is to add wiring for new dome lights....I am going to add two lights under the dash. And, of course, you need to plan on where to pull pigtails to power new gauges, and where to get grounds. I am adding a new ground where I bolt the new gauges to the dash. The existing light switch needs to be grounded for the dome light switch ground, and the new gauges need more pigtails....lots of pre-planning needed.
I don't know about the 1966 Fury but on my 1968 Fury's if you unbolt a bunch of lower dash mounts ie the two kick panel bolts that are slotted to hinge the dash install, and a couple of lower dash braces you can pull out the bottom to give you more room to work. I can't remember if you have to do the steering column and I think the FSM references this method in Heater A/C box unit removal.

I have been on my back under a lot of dashes for this kind of work. Not fun. This time, I have removed everything, that now has big open gaps that make it easier. The amazing thing is that in this large car, there was no room to attach the new fuse panel.....there is a large bracket next to the column that I think may have held the OEM.....mine was toast so I know not. But I am surprised at how hard it is to find space under there for anything. I just tested the rear lights this am, and will roll up and store the small bundle where I connected rear tail harness to OEM, but even that takes space. Just interesting. I will look at mine to see how the metal dash is held in place....pretty massive. But, I have always wondered why the mfrs dont just make the dash a fold down affair so you can more easily access the back. Recently had a C5 vette with a bad blend door on driver side. The thing was hidden behind the upper side of the main instrument panel.....and you start by removing the console lower and upper covers, and then try to get the instruments out of the way....not fun.
Getting close to end of my wiring comments. Today I installed my new harness for the panel lights across the dash....did suggest to painless that they offer one....most dashes are similar in respect to the fact that the panel light power spreads from gauges, to speedo, to heat, clock, radio, and more. But you need a harness that has pigtails for all these lights. Interesting that my first actual panel light connect was to my new OP gauge. Sent my gauge pack to a resto shop a month ago, and crickets, oh well. I will work on my speedo lights before install, but the silly pins off the board are loose....solder or what, dont know. So, my new panel light pigtails in place for the dash.....hoping my final test is good and my first light will light up.
But, I have always wondered why the mfrs dont just make the dash a fold down affair so you can more easily access the back.
Heh, It's folds up, at least on the 1968 and up cars as the Graveyers Curz show demonstrates. With the windshield out you just place/slide the dash onto the kick panel bolts (that's why those brackets are slotted) and as your rotating it up attach all the connections and put your upper dash bolts in. Makes it easy for the assembly line workers. Mark even has built a test stand to run and test all the gauges like his engine run up stand, which I haven't seen him use lately. I guess he's had problems with some components on the *FREE* rebuilt dash not working. And when I mean free, in a Charger forum it was posted via a supposed life long friend that he gets all the parts for these restorations for free for the mention (pitch) on the show. Sounds very similar to our speedway owners business practice down here in Daytona Beach.

I worked for the navy building ships....and even though I started young with my 53 plymouth, I could not afford to have graveyard do a car for me.....although it would be great. So, I need to work on the wiring, the carb, the leaky trans and the bad steering, and maybe one day, this thing will get out of the driveway on its own power.....I hope. Roadkill, or maybe Infuriating (fury).