Chevrolet Cab 12 wiring
 

Hello,
I started to renovate electrical wiring on my Chevrolet FAT Cab 12, 1941. I am not sure whether the set of cables should go around the engine just on the right side and which way it should go to the left front light (above or under the cooler) and to the backside. Could anybody help me? I enclose the only pictures I have but these are from Cab 11 and I don't know if Cab 12 is the same...
And does anybody know where to buy a terminal box?
Thanks for any help,
Zdenek

Attachment 110093 Attachment 110094 Attachment 110095

Wiring Harness Info
 

Hi Zdenek


Unfortunately the MLU advance search is not as easy as one might hope, in particular Find Post from setting often seems to default to a short period of time.
Attachment 110112


Once you have fixed that then searches become more productive. Here is a Advanced search on the word "wiring" and Post Made By: Phil Waterman that I've narrowed down to those with information more directly related to Pattern 11 & 12.


Wiring Harness Info Search on Word “wiring"
The Snakes Alive CMP Wiring Project
http://www.mapleleafup.net/forums/sh...ghlight=wiring

wiring harness
http://www.mapleleafup.net/forums/sh...ghlight=wiring

Rewiring
http://www.mapleleafup.net/forums/sh...ghlight=wiring

Wiring rehab
http://www.mapleleafup.net/forums/sh...ghlight=wiring

Wiring loom Cab 12 F60L
http://www.mapleleafup.net/forums/sh...ghlight=wiring
http://www.mapleleafup.net/forums/sh...ing#post125598


Hope it will give you a start. I'll start looking through my Pat 12 C60L wiring photos to look for the most helpful.


Cheers Phil

Cab 11 and cab 12 .....
 

They are practically the same ....... the early cab 11 did not have front fender mounted parking lights the cab 12 did...... not all cab 11 had night driving lights shining on the rear axle cover........ Canadian models of the cab 11 that never went overseas did not have the blackout system used in Europe....although many Canadian Cab were retrofitted......

So find and use the wiring diagram from the early cab11 / cab12...I was surprised to see you using my own cab 11 nightmare......field mice had eaten away all the insulation leaving bare wires everywhere. I basically took wire cutters and removed everything.............. but......... I was fortunate that some one made for me a perfect copy of the wiring harness, every connector, every color code and gauge respected with all bare wires already tinned ready for soldering..... and every wire was tagged as to its purpose.

It was a simple matter of taking one colored wire....look it up in the maintenance book and do the connection. The routing of the wires was simplified by examining two spare parts cab 12 trucks and when stuck asking as many questions as possible on the Forum. Some difference of opinion will occur on the location of specific wires and sometimes it is hard to decide if the sample truck you are using is "unmodified" by the numerous previous owners or done as a military modification. It leaves you to decide how you want you truck to be.

I am not aware of any readily available complete and accurate CMP wiring harnesses ........ it is labour intensive to fabricate so the cost his or would be high....... connectors and proper modern wiring with the original color codes are available for automotive restoration and are lurking on the web.....

I have converted, at the time of the wiring, to a modern 12 v. alternator which required thinking but not that complicated.....and added a rear axle light and turn signals as the wiring harness was built with the extra wires required at the time of assembly.

A lot has been said and written on the Forum and maybe we need a "sticky" devoted entirely to wiring cab 11, 12 and 13 Chevrolet.....and then you have the similar but different Ford cab 11, cab 12 and cab 13.......

I will try to help you out with questions and pictures........ you now see what I had to start with........ it is do-able...... just need to be patient.

The big SECRET is that Phil Waterman fabricated my harness..... one of 3 he ever made...... and have been ever grateful since.

Maybe the answer for future wiring snake nest is to document how to make your own using large plywood sheets painted white like the illustrations on Phil's web site and follow the diagram in the books. The big question is to arrive at the exact or near lenght of each wire before cutting it off the spool.
And to be economical you need to buy many spools and bags of fittings/connectors..... leaving you with enough wires/pars to make a few more... BUT be careful ......selling them may not be as easy if you try to recover you time and efforts some people will not pay the fiddler.

Currently I am aware that a full Dodge M37 wiring harness is around $1200 US........... that reflects the efforts and hand work that must be done to make and accurate copy........ oh and it comes with a multi page phamplet of instructions.

Grab your courage and wire clippers and go for it.

Cheers

Thanks again Phil!!!!!!!!!!!!!!

I believe vinwire in Australia makes a harness for the 11/12 cab trucks. They made my harness for me and I was very happy with it.

Indeed they do, and I too was rather happy with the product. A few reference photos in post 11 here:

http://www.mapleleafup.net/forums/sh...hlight=harness

They told me their Chevrolet cab 11/12 harness pattern came off a Cab 12 FAT, btw. :thup:

Owen.

Pattern 12 C60L under the hood
 

Hi Zdenek


Hope these photos will help with the routing of the wiring harness under the hood. What is shown is my C60L Pattern 12 with a new wiring harness, it was installed based on the existing original harness that was pretty much intact.

Attachment 110141

Attachment 110142 Attachment 110143 Attachment 110144

The wire attachment blocks shown are from a Jeep parts source and are a match for the originals.


Cheers Phil

I think part of the reason why the early M-series harnesses seem to be ridiculously priced is that the prices for the components are beyond ridiculous. The shells and the bakelight unions are bad enough, but the little rubber grommets, which are usually the failure point to the connections, are 75¢ each. Then add to that the almost impossible to find 14 and 12 gauge double grommets used around the circuit breakers, and one quickly find out why the somewhat simple harness costs more than those for a brand new vehicle.

Thankfully, the M-series rubber (it think it's hypalon) coated wire is still manufactured and available at reasonable prices. Personally, I think it is just about the best wire one can use....it certainly has a very long life span.

Hello everybody,
thanks a lot for your answers, it helped me to go on with the restoration.
So far I managed to connect recharging and ignition...

The blocks are from Jeep? But which type? What I know it has more attachments... Or did you modify it?

Zdenek

Generic junction blocks
 

The blocks shown by Phil is a generic and is sold by quite a few restoration retailers, Chevs of the 40s, Jim Carter,etc......

For the cab 11/12 the 3 connection ones are what I have seen as originals.....you can use one of the mounting end screws for a ground.

Good luck