The Snakes Alive CMP Wiring Project

[Phil Waterman]

Originally Posted by 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

Hi

Thanks Grant, I was in the process of digging out the same photo, that is the wiring from my 1945 HUP, I'll now try to find the photo of the 1942 C60S wiring harness.

But I suspect the difference is just evolution of CMPs they did make ongoing production changes in responses to reports back up through the maintenance channels. The logic I see to all the nose lights all coming to the same terminal blocks is it really annoying when you are pulling the nose off a CMP is to find you just ripped out a wire. It takes me 20 minutes to take the nose off Pattern 13 Cab which makes it a lot easier work on the engine. If you had to chase around and find all the connections it would take longer.

Cheers Phil

[Jacques Reed]

Good Day,

I’ve decided to re-do my 25 year old wiring harnesses on my F15-A.

A number of reasons:
Basically back in the mid-nineties I copied non-original harnesses that were on my first truck. At that time I did not even have a Repair Manual for a wiring diagram so I copied the colours and wire gauges as best as I could estimate from the existing harnesses. A bad call in hindsight.

Interestingly, those harnesses I copied used plastic covered wires but they were in original looking woven cotton shrouds. I am surprised they weren’t cotton braid covered wires, but perhaps someone went to a lot of trouble to run wires through the original shrouds even if wrong colours were used.

Another consideration was adding turn signal wires. I know it isn’t original but I believe it is essential in modern traffic to have them. The wires are less obvious inside the new original style harnesses. I made them slightly longer to differentiate them from the original wiring and give a bit more clearance at the solenoid.

I also wanted to add the Autopulse wire to the harnesses. Although not used on Australian vehicles it could come in handy to add an electric fuel pump, if required, at a later date. The wire was fitted originally even if not used but I left it off my first version.

I had hoped to use cotton braid covered wire but I opted for modern automotive wire instead. In reality, very little of the wire is visible so I couldn’t justify the high cost of a commercially made harness. I would not be able to reproduce the woven cotton shrouds anyway so it made even more sense to go with modern wire. I used vintage style bitumen impregnated conduit for the shrouds instead which, although not original, looks in keeping with the era of the truck. I spent about $175 for all the materials.

I obtained a rough, but complete, main harness a while back and a NOS horn (lower chassis) harness for patterns. Over time, I have measured all the lengths of wire and tabulated what I needed in colours and wire gauge.
I used Tycab Australian made automotive wire throughout. I tried to use trace wires wherever possible to identify the wires similar to the original colour coding. In some cases the wire/trace colour combinations were just not available however. In those cases I added a length of heat shrink tubing of the appropriate trace colour to identify it.

I made one exception to the original colour codes. I made the horn wire from the solenoid orange/green band to avoid confusion with the left fuel sender. Both are normally yellow/green x 2. Only a few inches of the horn wire at the solenoid is visible so I can live with that.

So the instrument panel is done, the horn harness is done, so just the main harness to finish off. All wires for it have been cut and run so a just bit of soldering to finish it off.

Hope this is of some interest.

[Jordan Baker]

Very nice work.

[Jacques Reed]

Good Day,

Thought this may be of interest. Found these yesterday in a junk shop in Melbourne. NOS 6V Ford script headlight globes.

Interestingly they say "Made in Holland" on the base.

I guess it is safe to assume that they were made post war! Part No. indicates a 1941 design. Must have made them for only a short time afterwards as sealed beams were in common usage by then.

You just never know what will turn up 70 years later.

Just noticed in Parts list * C01Q 13009 Bulb 32-21 C.P. 6-8 Volts is lower candle power on High than these at 50 C.P. on High. Better illumination with these ones but draws more current.

Cheers,

[m606paz]

Can help me with this Ford wire no listed in part list?

[Andrew Rowe]

Part number would almost suggest that this is for a Rear - engine armored car,
For the Indian Pattern one's, armored cable, Cheers Andrew.

[Jacques Reed]

Some aspects of the following may have been covered before on MLU but it may still be of interest to restorers.

I have noticed most wiring diagrams in Ford CMP Maintenance Manuals and Handbooks do not show the wiring for an ammeter equipped instrument panel. A discussion about wiring with a fellow MLU Member prompted me to investigate it a bit further. The only reference I could find was a 1945 Australian “Drivers Handbook for Ford” which showed an “Ammeter” in the dashboard layout diagram. All other publications show it as a “Battery Indicator” There are also some wartime Ford commercial truck wiring diagrams showing an ammeter and not a battery indicator.

Thanks to Mariano Paz’s 1945 Ford CMP wiring diagram data plate, my original harness, and the link below I have a clearer picture. Also going back to Electricity 101- Ammeters vs Voltmeters helps to make it clearer. Ammeters- measure current flow in a circuit and placed in series. Voltmeters- measure electrical potential difference between two points in a circuit and placed in parallel.

1939-40 Fords, Mercs, and Lincolns, and early war CMP’s used a gauge with “BATT” displayed on the face which is really a voltmeter. Ammeters display “DIS-CHG” on the face. Later in the war, the Ford commercial instruments, used in the CMP’s, were changed from battery indicators to ammeters. This was prior to the military round gauge instrument panel being adopted. As of the May 1943 F15-A Spare Parts List. however, only “Battery Indicators” are listed, and not ammeters.

On indicators with “BATT” displayed the current flows from the starter solenoid first to the voltage regulator battery terminal, then to the ignition switch, and then to one terminal on the Battery Indicator. The other terminal on the indicator goes to earth. This is shown on all the early wiring diagrams and is correct. I must admit I thought in the past that was wrong but I was looking at my ammeter’s wiring and not that of a voltmeter.

When the Ford commercial ammeters replaced the battery indicators on CMP’s the wiring could be the same for both the Ford gauges and the military round gauges. The current flows from the starter solenoid to the ammeter first, and then to the voltage regulator battery terminal. If an early BATT gauge harness is used on an ammeter equipped truck or an ammeter harness used with a battery indicator equipped truck it could cause serious electrical problems.

Things to keep in mind if repairing, making or buying a wiring harness, or changing gauges.

And yes, the battery indicator and oil pressure gauges are on the wrong side in the photo and “BATT” should be on the bottom. That’s how I bought it.
I have been told the gauges are the same and can be used if you change the faces, but you can only swap a BATT, not an ammeter, with the fuel gauge, and the temp with the oil pressure gauges due to the mounting hole positions.

Hope this is of some help and interest.

The following link may help to explain it all.

https://fifthaveinternetgarage.blogs...gauge-and.html