The Snakes Alive CMP Wiring Project

[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

[Jacques Reed]

Good Day,

This is probably a question for the Australian members as it is about the wiring to the two headlights on those Ford CMP trucks with Australian cabs.

Just trying to nut out the wiring on the front cowl from a very ratty remnant of a cowl harness and upper terminal block. The Ford CMP Maintenance Manual does not cover the wiring from the dip switch to the Hi and Low beams of the two lights as used on these trucks so it is not the final word in this regard.

I have traced out the wiring as best I can with a multimeter and exposing some of the original colour wire. The wiring to the left side of the cowl seems pretty straightforward from the remnant. Looks like the left sidelight has about a 24" tail on it to connect to the harness as shown in last photo. A 24" tail on the right sidelight would nicely connect it to the single wire No. 6 shown in the photos. Likewise the tails on the right headlight, if the same length as those on the left side headlight, would connect nicely into the short tails at the terminal block. We all know how Henry liked to keep it simple and common.

The short tails on the Hi and Low beam terminals have me wondering if a double connector was used at those positions from the dip switch to the terminal block. It would also allow the right hand headlight to be plugged into them. See example on the low beam wire No.4. Not shown is the Hi beam indicator wire which I assume attaches to the terminal strip with an eye or could also be plugged into the back of a double adaptor with a bullet end if used? The other option would be to use an eye end to the Hi and Low beam terminals at the back side but I don't see any sign that ones were ever attached there.

I am also guessing that the power from the light switch goes to a terminal on the lower terminal strip and then to the dip switch input terminal.

Does anyone have an original dip switch to terminal block harness to compare, or have seen original double connectors used there?

Cheers,

[Keith Webb]

Here are some I took of one of Tony Wheeler's F60S a couple of years ago - a pity it's too dirty to see the wire codes but you can see the doubled up wire on the terminal block. Sorry I didn't trace and number them!
Hope they help - it's not often you come across original wiring these days.
The wiring to the dipswitch is perilously close to the clutch pedal and you can see how it has been wearing on one of the wires. The terminals are also very close to the splash shield which is often either removed or has been cut away in that area.

P1030734.jpg P1030740.jpg

P1030735.jpg

[Jacques Reed]

Hi Keith,

Thanks for that information and photos.

It answers two questions:
It doesn't look like double connectors are used even if they would do the job, and it appears the leads from the dip switch go into the rear of the middle and lower terminals of the upper junction block (Hi and low beam respectively)
I will therefore connect the right headlight to the short tails at the junction block with just single bullet connectors and bring the leads from the dip switch to the rear of the junction block.

I will wire it up that way unless something else comes along to prove otherwise. I notice there is a small clip on the foot plate near the clutch pedal bump pad which may help to prevent the dip switch harness from getting chafed.

Thanks again,

[Jacques Reed]

Good day Again,

Next question: I noticed on some headlight reflectors I have salvaged that some had an extra hole above the main headlight globe with a smaller globe fitted there. Some reflectors I have found didn't have this extra hole.

The parts manual shows the smaller globe fitment for both the early and later cabs.

So the question is where does the smaller globe fit into the scheme of things?

With a twin filament headlight globe it would not be the Low beam.

Is it wired in parallel with the sidelights so that in effect you have parking lights on when you have the sidelights on? This would however result in the parking lights being on when switching on "Tail & Side" or "Tail, Side & Head" This might not be acceptable to the military for darkened driving.

Perhaps they were just a later replacement for the single base reflectors and the small light was ignored and never connected.

I probably will run sealed beams anyway for the greater road safety they provide. I don't always pursue 100% originality where safety is concerned but it would be nice to know where those small lights in the reflectors fit in on Australian CMP's.

Thanks for any help or any ideas on the subject.

Cheers,

[Lynn Eades]

Hi Jacques. The small bulb is the park light. The headlight bulb has high/low and earths through the body. Were the park light type just standard commercial ones from cars that never had separate side lights?

[Jacques Reed]

Hi Lynn,

Yes they were just small bayonet globes and I see that type of reflector is still available for old civilian Fords that had the parkers in the headlights. It still doesn't make sense what they are doing on a CMP truck if there is no dedicated switch to control them.

The reflectors, single and double light bases, definitely came out of various Ford CMP trucks that I scrounged. There is no reference to parking lights in any CMP manual that I can see.

I am thinking more and more maybe they used whatever was available during the war and if they were short of single light base reflectors they threw in double base ones. Just because they were there they didn't have to be connected perhaps? Still doesn't explain why double light base reflectors are shown in the parts manual however. Hmmmm!

Cheers,

[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.

Headlight installation 2.jpg

[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?

[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?