The Snakes Alive CMP Wiring Project

[Jacques Reed]

Originally Posted by John Winfield

Phil:

Thanks for your info - I had already looked it over and it was very helpful. But there seem to be some basic differences between the Ford and the Chev (voltmeter vs ammeter, for example). I probably got about 75% of what I needed. I guess I'll make my best guess for the rest, and when in doubt - go a little thicker.

John

Hi John,

This probably is a bit late response but it may be of some help.

Most of my wiring on my F15-A has been done with 14 Gauge wire. I used 10 gauge on No.36 generator armature wire and No.38 solenoid to voltage regulator. I used 12 gauge on No.34 generator earth and No.35 generator field. These were the gauge wires I found on the original harness.

The outside diameter can be deceptive as the original wires had a thicker covering. What matters is the number of strands in the wire and the load it can carry.
Also some suppliers measure the strands in imperial sizes and others in metric. Some use Nominal sizes 4mm, 5mm, 6mm which has no bearing on the outside diameter or core diameter. All this can add to the confusion of wire selection.

I haven't seen any original 20 gauge wire on my truck. There may have been some 16 gauge wire used in the dash lights, hi beam indicator, and trouble light socket but I opted for 14 gauge all around. I have attached a photo of a wire comparison card I made up a while ago. It may be of some interest.

Cheers,

[Keith Webb]

Hopefully this is helpful Jacques.

[Jacques Reed]

Hi Keith,

A great find and will it be very helpful! Answers a few wire gauge size questions too. Many thanks for posting it. I noticed the remains of fork type terminals on mine too. Guess this makes for easier disconnection if one wants to remove the cowl and not lose terminal screws.

Cheers

[Jacques Reed]

Hi Keith et al,

That diagram was a great help. Attached is a wiring diagram I made which may be of use to fellow restorers. Between your diagram, the remnant of a dip switch with a bit of the harness left, and the remnant of the cowl harness and terminal blocks I think it is all correct but, as always, glad to hear from anyone if there is an error.

There are some wires not listed in the Parts Manual wiring diagram but on your diagram due to the two headlight configuration: namely 1a, 2a, and 4a

The wire gauge sizes are off your diagram and match the remnants I have found. The lengths are the wire lengths as measured off the cowl harness from bullet to terminal. The lengths of the dip switch harness wires are my best estimates and may require adjustment.

The turn signal wires are purely for my benefit to agree with the Falk turn signals I have installed.

Cheers,

[John Winfield]

Finished my rewiring job a week or two ago (well, almost – no high beam indicator circuit). In the end, gave up trying to duplicate the existing wiring, since it was in such rough shape, and just pulled it all out and rewired to the manual. I even went so far as to create a quick 3D model on CAD to get a guess at wire lengths (that's the brake circuit showing).

I've also added a couple of before and after shots:

It's still a little rat's nesty behind the dash, but maybe I'll get back in there some day to clean it up (but probably only if I have problems). Some other wires are a little long, so I may trim them back at some later date.

I made a few changes from the manual. I put in two regular tail lights. There's no sign of the small tail lights on my CMP, or the switch at the back for the differential light, so I didn't bother with them. I also wired up the switches so the side lights are on their own switch, without it lighting the tail lights, or the head lights lighting the side lights. Probably shouldn't have bothered with the brake isolation switch either, since I'll probably hit it accidentally a few times. I set up the inspection light socket, but didn't actually hook it up – don't think I really want a live socket up there.

I did buy a few little harnesses from MAC's. I got headlight harnesses, a cross harness for the tail lights, a Mercury harness for the instrument lights, and I also got a cowl light repair set to do the side lights. Unfortunately they are sold out of the high beam indicator harness, with no word of when they'll be back in stock.

The lights all seem to work as advertised (once I put in a new brake switch). The engine turns over and the horn works, but I haven't started it since the rewire for other reasons.

I bought my wire from Rhode Island Wiring – they seemed to have the biggest selection of colours. Also, most of the connectors. I crimped the ends, on the advice of a friend who does wiring on helicopters. He showed me a fancy crimper that crimps from four sides at one time, and serendipitously happened on a much cheaper version at an estate sale the following Saturday, when I went over to Buffalo NY to buy some 6 volt sealed beam headlights.

I'm a lot more comfortable now, having gotten rid of that old wiring.

John

[Jordan Baker]

Does anyone know if the Wireless CMP trucks had fully shielded wiring harnesses similar to what’s in my picture?

[gjamo]

I have 3 NOS wiring looms that I bought years back. Two I think are Chev and 1 is Ford.The switches are cruder than I have seen on my blitz so may assumption is that they are early, possibly cab 11/12. Does anyone recognize them?

[Ganmain Tony]

Fairly confident they are Ford 12/11 Cab Graeme

[Hanno Spoelstra]

Originally Posted by gjamo

I have 3 NOS wiring looms that I bought years back. Two I think are Chev and 1 is Ford.The switches are cruder than I have seen on my blitz so may assumption is that they are early, possibly cab 11/12. Does anyone recognize them?

Can't read the part number, but they look like these posted on page 1 of this thread:

Originally Posted by Hanno Spoelstra

“WIRING HARNESS. Thought to be for the early style cab, 11 & 12 Ford. Never used. 4 switches, 3 light sockets. Metal identification tag C11Q-14401C.“

C11Q-14401C is the latest version of "Wiring - cowl" for the Cab 11 and 12 - ref. http://www.mapleleafup.net/forums/sh...334#post222334

[David Dunlop]

Jordan.

For most of the wartime production, that shielded harness was the type used for all Wireless Vehicles, all weight classes. Two identical harnesses were in production: the standard cloth loomed ones used on none wireless vehicles, and the metal shielded looms for wireless as you have shown.

At some point late in the war, I do not know when, the practice of producing two separate wiring harnesses stopped and only one was produced thereafter. This final version was essentially a shielded harness like you posted, but with an extra overlay added, the outer jacket is some sort of fibre/cloth impregnated with a black, tar like substance.

I have been told that once the final version arrived, it was to be used as replacement harness in all vehicles. Perhaps it was felt that all transport would benefit by better electrical shielding and from that point on, only Wireless Vehicles had the extra ignition shielding added. It has also been suggested the extra jacket over the loom was a corrosion prevention asset.

In any event, you are OK with the shiny shielded harness on a CMP Wireless Vehicle.

David

[Jacques Reed]

Good Day,

With another year closing I thought it was time to finish off another loose end. I wanted to rewire the wire tails on the various lights on my F15-A. All of them had hard brittle insulation and the light base contacts on some were in poor shape.

Backtracking a bit: A year ago I had a local gasket manufacturing company make me some 15mm diameter fibre washers to replace the base contacts on those lights. Interestingly they did not stamp them out but used a high pressure water jet to cut them.

My originals had a small eyelet in the middle into which the wire was soldered. I note some light bases used a rivet on the wire end instead, but all mine had eyelets.

I obtained some brass eyelets online and installed them in the disks after drilling the holes for them. The material was too tough to use a punch and anyway I wanted to make the holes as accurately as possible on centre.

I made up a jig to hold the wire and base contact for soldering using a piece of wood. I drilled a 5/8" diameter 2mm deep recess with a wood spade bit then followed through on the drill press with a 4mm diameter hole. This made a nice firm fit to hold the wire and located the contact right in the center. I filed a groove in a soldering iron tip to make contact with the wire and rounded the back to contact the eyelet. Didn't show it here, but I used masking tape to hold it down in the jig during soldering.

With a couple practice runs it was a simple job to get a perfectly soldered contact. In fact, looking at my originals I am much closer on center than the originals in some cases. Two things to remember however: tin the wire end first and do not hold the soldering iron tip to the eyelet and wire for more than about 5-10 seconds. My first attempt heated the wire too much and made the plastic insulation swell which made it hard to remove from the jig and one to be scrapped.

Hope this is of some interest and a Merry Christmas to all.

Cheers,

[Jacques Reed]

Good Day All,

Tidied up another loose end- no pun intended, with the cowl wiring for an Australian CMP two headlight cowl.

Finished the small harness from the terminal block to the dip switch thanks to Keith Webb's diagram. Noticed a hole in the splash guard which just begged having a clip there to keep the harness from rubbing on the clutch pedal arm.
Checking two other splash shields all three had an identical hole at the same place so obviously it had some purpose. I will take a punt that it was for a clip for the harness to keep it off the clutch arm.
Without a sample of that harness, I took an educated guess at the wire lengths. Possibly longer than original but they can be shortened if good info comes to hand.

I also fabricated the harness from the terminal block to the lights. I used a very rough original as the pattern which gave me accurate wire lengths. I also added turn signal wires to it with bullet connectors for easy removal should I ever want to remove them.

Although not 100% original it is as close as possible as I could make it. I used fork terminals or ring terminals where required and attached them to the terminal block in the same manner as shown in Keith's diagram. Covered the ring and fork terminals with silicon rubber self-vulcanizing tape.

Original harnesses were covered in a braided sleeve at manufacture but I used bitumen-impregnated cotton loom. Slightly bigger diameter than original harness to accommodate the two extra turn signal wires.

The lower two original unused terminals were just right for the turn signals.

Hope this is of some interest.

Cheers.

[Keith Webb]

That's an essential clamp on the splash shield, great work Jacques.

[Jacques Reed]

Hi Keith,

Thanks again for your help.

Here is a revised cowl wiring diagram based on the diagram and photos you supplied which may be of help to others. It shows the corrected entry of the various ring and fork terminals on the terminal block.

I made the turn signal wires an extra 4" longer than the side light harness wires to avoid wrong connections. Yellow is the colour for the sidelights and for Falk turn signals front left side.

As previously mentioned, the lengths for the side light and headlight wires are correct as per my original sample. The wire lengths for the dip switch harness are my best estimate. If anyone has an original harness for the dip switch I will gladly revise my wire lengths if they are different.

Cheers,

[Jordan Baker]

Just wondering if anyone has some photos showing where the rear harnes goes from the change over switch to the light positions? The harness I got from Vintage Wiring Harness Australia doesn’t seem to make sense

The truck is for a C15a. It shouldn’t make really any difference if it’s cab 11/12 vs 13

[Jacques Reed]

Good Day,

Following on from the "Toggle Switch" thread in the restoration section here is a revised diagram of the later Ford CMP light switch wiring. Revision shows the internal common connections at the input terminals.

Note: This is for the later light switch panel which used specialized TPST switches to control defined groups of lights. Earlier light switch panels operated individual types of lights only and can be operated using SPST switches.

All lengths taken from an original harness. Wire numbers and colour codes as per Ford wiring diagram.

Hope this may be of help to other restorers.

Since posting this I had a look at another light switch assembly and found some interesting differences. At first I thought it had been jury rigged using a SPST switch at the Tail light. Upon close inspection and tracing out the original wires it appears it could be an original setup also. The jumps were factory crimped and when I analyzed it, TPST switches were not required at every location to obtain the lighting combinations. See my comments in "Toggle Switches"

Attached is the original wiring showing the crimped terminals and another wiring diagram using the switches in the photo.

Cheers,

[Dave Schindel]

just wondering if anyone has found a supplier for bullet connectors for the F15a cab 11 ? The old ones are all crimped on so can't be reused . Need 2 different sizes at least. The big ones are .240 OD bullet and the smaller ones are .190. I am using original cloth type wire of the correct color and would like to make the proper connections. Any ideas?
dave

[Owen Evans]

Originally Posted by Dave Schindel

just wondering if anyone has found a supplier for bullet connectors for the F15a cab 11 ?

Can any of these folks help?

http://www.riwire.com/

https://www.vinwire.com.au/accessories.htm#conn

https://www.autosparks.co.uk/electri...r-sleeves.html

Owen.

[Jordan Baker]

Ive gotten various wiring bits from Rhode Island before. They are great to deal with. Its best to just call them and chat on the phone.

[Bob Carriere]

https://restorationstuff.com/

Good luck

[Grant Bowker]

Originally Posted by Dave Schindel

just wondering if anyone has found a supplier for bullet connectors for the F15a cab 11 ? The old ones are all crimped on so can't be reused . Need 2 different sizes at least. The big ones are .240 OD bullet and the smaller ones are .190. I am using original cloth type wire of the correct color and would like to make the proper connections. Any ideas?
dave

Looking at modern spade quick disconnect for a project unrelated to CMP I was surprised how many variants there were close to 1/8" but none of them actually 1/8". I know that there were several profiles and sizes close to the original CMP bullets the last time I looked. Moral - check carefully to be sure you get correct, or at least compatible, sizes.

[Dave Schindel]

Thanks for all the help guys. The ones that are available are slightly different sizes but I am sure they will work. Likely going with riwiring for a supplier.

[Jacques Reed]

Originally Posted by Dave Schindel

just wondering if anyone has found a supplier for bullet connectors for the F15a cab 11 ? The old ones are all crimped on so can't be reused . Need 2 different sizes at least. The big ones are .240 OD bullet and the smaller ones are .190. I am using original cloth type wire of the correct color and would like to make the proper connections. Any ideas?
dave

Hi David,

Just stumbled upon this company, The Brillman Co. in Virginia USA. On page 16 of their downloadable catalogue are two sizes available 0.156" and 0.180" diameter. Perhaps the 0.180" would suit.

Great stuff in the catalog. Cotton braided covered wire with various traces available and US made quality to boot. There is only one source of that type of wire here in Australia.

Pity I am so far away and the freight is much more than the cost of the items. I wanted to visit a few more Civil War Battlefields so perhaps that is a good excuse to go to Good Ole Virginny!

Cheers,

[Jacques Reed]

Good Day,

In the process of renewing some wiring I noticed some errors in my previous post on the lighting panel wiring. I have upgraded the diagrams accordingly.
Basically 16 gauge wire was used for the jumps, lead to the inspection socket, and dash lights instead of 14 gauge wire.

This became apparent when I compared the three wires on the cowl terminal block to the drawing supplied by Keith. see attached. This gave me a good reference point to determine the sizes of all wires on an original harness fitted to a late war dash. Checking good sections of the wires with a vernier eliminated the eye being fooled by colour or light.

As a general guideline, the wiring between instruments, dash lights, inspection socket, the resistor and coil, start button to solenoid, and wires connecting sending units are 16 gauge (same size as high beam indicator wire). Wires for the jumps between the switches are 16 gauge also but attach to 14 gauge wires on the main harness. I believe the reason for this is two wires into a bullet require smaller gauge wire to fit and as the wires are close to the power source and short, the voltage drops are negligible.
Wires to the tail, side, and stop lights are 14 gauge (same size as side light wires). The wire to the headlight terminal on the cowl is 12 gauge but the tails from the block to the two headlights are 14 gauge. The stop light isolation switch out wire is 14 gauge as there is only one wire connected to the switch on the output side. The longer runs to the tail and stop lights require larger 14 gauge wire to reduce the voltage drops.

There may be other variations based on wartime expediency but these sizes are correct as measured on an original harness.

Cheers,

[Jacques Reed]

Good Day,

I have just redone my wiring from the ignition and fuel tank gauge switches in the course of redoing all my wiring. I redid did the light switch panel a couple weeks ago.

The interesting thing I discovered using an original harness for a pattern is the Autopulse wiring. Even though the Autopulse was only fitted to Indian delivered CMP trucks it appears the wiring for it has been fitted to the harness of at least one Australian Ford CMP also. Perhaps one size fits all by Ford.

As per attached photos:
Wire No. 45 is a jump from the ignition switch- out to the Autopulse switch in. When the ignition switch is thrown current to the resistor and the Autopulse input side flows.
No current flows to the Autopulse unless the Autopulse switch is also thrown. So you can run the engine without the Autopulse on but cannot run the Autopulse unless the ignition switch is on.
No. 46 wire is fitted to the main, and lower chassis harness also and terminates near the starter relay with the other tail, stop, and fuel tank sender wires.
No.16 and No. 45 doubled up at ignition switch to resistor and not at No. 30, ignition switch to gauges, as shown in Special Pattern Vehicles diagram. Not the first time diagrams and reality differ.
Again, all wires are 16 gauge except No. 21 which is 14 gauge.

Hope this is of some interest and have a safe and healthy Easter.

Cheers,

[Jordan Baker]

The wiring for the front marker lights, does it go directly to the junction block mounted on the inside of the nose or was there a separate junction closer to the light?

[Grant Bowker]

I don't recall ever seeing any evidence of an intermediate junction block and the diagram in section 2.605 of the parts book shows the sidelights with connectors to suit the central junction blocks. On the other hand, I don't remember seing light assemblies with long wires as replacements - maybe because so many were damaged by trees they were all "field expedient" repaired, extended or whatever... and none left for NOS sales?

[Phil Waterman]

Hi Jordan

I've encountered marker lights with long tails with spade ends long enough to reach the terminal strips up on top of the footwells both sides. Have also bought NOS marker lights with short wire tails about a foot with plug ends for inline connectors.

Cheers Phil

[David Dunlop]

Hi Jordan.

According to MB-C2, the two terminal strips either side of the cowl take headlight wiring only. The circuit diagram shows the two side lamps feeding directly to their switch on the dash. Whether that is a direct, long lead feed from both lamps to the switch, or shorter length leads that get the wire inside the cowl and then connect to fittings on the main cowl section of the wiring harness is unclear.

David

[Grant Bowker]

Agreed that the page in MB-C doesn't seem to show the markers going through the junction block but that doesn't make much sense to only make it easy to disconnect part of the wiring.

A reliable source shows a photo of an unmolested wiring harness removed from a known original vehicle and clearly shows wires in the main harness of the same (+/- a tiny bit) length to connect headlights and markers, all through the junction blocks. http://canadianmilitarypattern.com/R...arness%203.JPG