72 3.0 CS 2240344 Restoration

[ScottAndrews]

Side markers were on all US, North/Central/South America deliveries for sure. They are on with running lights/license lights, harness makes sense to me. That is why all coupes have a four digit model code that allowed the assembly line workers to know if was for Europe/ROW, LHD/RHD, manual/auto, 2800/3.0, pre 74/74 and on, etc.

It does make sense as a modification to the existing harness. it is, however, not very space efficient.

I did locate the seat belt wiring. Interesting, it appears there is a sensor in the passenger seat, and an entirely separate harness that runs from the seta belt mounts forward into the dash. I'll dump that, since I will have no dash mounted seatbelt display.

 

[ScottAndrews]

OK, having some phun now!!!
Got all the wires out of the car with the exception of a wire that goes through a separate firewall feedthrough and down to the transmission area. Not sure what that is for, and one of the two wires is clipped.

This was a long tedious job that involved labeling every wire I disconnected, and then carefully feeding long sticky and dirty wire bundles through cramped spaces. I made comprehensive notes and took lots of photos. There are numerous bits of odd non-stock wiring up around the fuse box, including spade connectors that are not connected to anything, etc.

Since I am not removing the headliner, I labeled and clipped the wires to the dome light (at the driver's side A-pillar). I'll put a spade connection on that when I re-assemble things

I am replacing the fuse box with one of Galahad's blade fuse units, but I labeled every wire, so when I go to install that I won't have to track down every wire.

Once the car body is gone I'll lay out the harness on a wood frame in its basic geographic configuration, and start matching the wires with the numbered wires in the wiring diagram. That should help me sort out the non-stock wiring as well as identify a few wires that were not connected to anything.

While this was a big job, and will be a big job to re-install after the big job of replicating it with new wires and connectors, I am glad I did this. The layout makes sense, so re-assembly should be OK, and a new harness will be easier to install. Having the old wiring out will mean the body shop can clean and paint the entire car, inside and out, so a very fresh and clean start to re-assembly.

 

[ScottAndrews]

you can unplug everything in the engine compartment (labeled of course) and pull everything into the interior still hooked up to the fuse box and remove the entire harness. the hole in the firewall is like 30 or 40 mm

It was actually easier to go the other way. Once the wiring under the dash was all disconnected from the fuse box and a couple of spade junctions, the wires pulled through into the engine bay with relative ease. I then just lifted the harness out of the engine bay, relays and all

 

[e9Leveque]

One option to consider - I decided as I was rewiring to make some items a bit modular to allow easier revision/repair later. For example for the wires that feed into the relays for the window motors I added connectors so that changing out motors later is an easy disconnect/connect. While in some cases this could add a point of failure with the connector, the ease of further change seems to make it worthwhile. Essentially any place where the wiring becomes hard to access I added a connector so I can easily separate the two halves to deal with independently. Likely overkill but easy to do

 

[rsporsche]

It was actually easier to go the other way. Once the wiring under the dash was all disconnected from the fuse box and a couple of spade junctions, the wires pulled through into the engine bay with relative ease. I then just lifted the harness out of the engine bay, relays and all

i was thinking about leaving everything connected to the fuse box and all the relays / switches

 

[ScottAndrews]

i was thinking about leaving everything connected to the fuse box and all the relays / switches

I suppose you could do it that way, but the front harness is pretty long, and you would need to remove and label all the wires to the engine bay relays. I'm changing out the fuse block anyway, so removing it was easier (although it did involve a LOT of wire labeling!!)

 

[ScottAndrews]

One option to consider - I decided as I was rewiring to make some items a bit modular to allow easier revision/repair later. For example for the wires that feed into the relays for the window motors I added connectors so that changing out motors later is an easy disconnect/connect. While in some cases this could add a point of failure with the connector, the ease of further change seems to make it worthwhile. Essentially any place where the wiring becomes hard to access I added a connector so I can easily separate the two halves to deal with independently. Likely overkill but easy to do

Great idea.

One area that drove me nuts was the door harnesses. They use those square spade connectors to link the door harness to the main wire loom in the kick panel area. The problem is these connectors have a free side and a fixed side. The free side unplugs, but the fixed side is embedded in the plastic housing. On my car the fixed side was attached to the main loom INSIDE the grommet feedthrough. The two wire connector is too wide to fit through the feedthrough, so there was no way to get the loom free. So I had to pull the fixed side out of the connector. I'll probably replace those with the connector the other way round.

As I go through the harness I'll identify the places where it would make sense to break up the wiring. For a general purpose car, I get the concept that they want to save cost by minimizing connectors, and also reduce potential failure points, but this car is never going to be a daily driver, so some advance planning and a little attention to maintenance and configurability makes sense.

 

[ScottAndrews]

Some additional detail on my geographic map of the wiring harness. This corrects some of the looms around the console and the instrument panel.

Still need to sort out the details of the IP/fuse box, and the engine bay.

Seems that in addition to the fuse block, there are two cluster connectors (#60 in the diagram), 2 spade connectors (#37 - 5 position, and #40 4-position), and two large connectors (#57 9-pin wiper/indicator, and #59 5-pin Dip switch). There nay be a handful of other single spade connectors as well.

Note: this is for a 1972 US Carbureted car.

 

[e9Leveque]

Great idea.

One area that drove me nuts was the door harnesses. They use those square spade connectors to link the door harness to the main wire loom in the kick panel area. The problem is these connectors have a free side and a fixed side. The free side unplugs, but the fixed side is embedded in the plastic housing. On my car the fixed side was attached to the main loom INSIDE the grommet feedthrough. The two wire connector is too wide to fit through the feedthrough, so there was no way to get the loom free. So I had to pull the fixed side out of the connector. I'll probably replace those with the connector the other way round.

As I go through the harness I'll identify the places where it would make sense to break up the wiring. For a general purpose car, I get the concept that they want to save cost by minimizing connectors, and also reduce potential failure points, but this car is never going to be a daily driver, so some advance planning and a little attention to maintenance and configurability makes sense.

The other place that I did this same modification was the fog lights. I had purchased some Marchal fog lights for the front bumper but wanted to be able to remove them easily. I added a relay in the engine bay but then used a simple connector in between the lights and the relay, so removal involves unscrewing the two lights, unclipping the connector and done. Same with the second horn (a Maserati horn) that a previous owner had added. New relay and then connector near the horn. I'll just leave it in but if anyone wanted to remove it that can be done without needing to unscrew terminals, chase wiring, etc.