Operation "New Electrical Wiring" on a GMC from 1944
Having old vehicles is also very much about friendship and network. It is clearly an interest that you need and want to share with other likeminded. You often find your self in a situation where you need help andva piece of advice and sometimes your assistance is not just around the corner, but in a far location. Nevertheless you are always ready to help and can expect assistance so we can all keep as many of these mighty vehicles rolling as a "active museum". This article is about two friends that pack up their gear and go to assist a third friend with the same vehicle but in need to upgrade the trucks electrical network. Welcome to "Operation New Electric Networks".
Written by Flemming L. Koch.
Ole Andersen and I (Flemming L. Koch) are the proud owners a GMC from 1941 which we have renovated.
During the restoration process, we needed to buy spare parts, which we got from another happy GMC owner, Jens Bekkelund who knows almost everything that you need to know about GMCs, especially the mechanical side of things. However he does not fancy dealing with the electrical systems. During one of our conversations, we told Jens, that we had made a new 6V electrical networks in our GMC, which has been a very good improvement that allow you to actual see something during night drive.
We offered Jens to come to Jutland and do the work on his GMC, which is from 1944. It did not take long before Jens accepted and we started the of planning our trip.
It was an extensive work to purchase all required parts for the GMC. Cables, switches, cable shoes etc. that was required for the project. It took almost a whole week, and I had fortunately found a place where we could buy Seal Beam headlamps for the truck. We bought most cables and cable shoes from Per Holm at Nyboes Auto. ( If you have a need to buy El articles for your old vehicle you can buy from him on telephone 56 96 26 50)
The project begins:
We left on Friday 12/9 in the morning and took the ferry and headed towards Jutland. We came to Stenderup in the afternoon and got a cup of "welcoming coffee".
After the coffee and a little talk, we started. The old GMC was ready and had been sandblasted and painted, but the electrical wire grid was in a very bad condition. Ole started to remove all the old cables from the rear lights, while Jens and Flemming removed the large main cables from the battery to ground / starter, after which they made new connections with 50mm3 cables with hand soldered lugs. All connection had shrinking Flex with glue so they would be waterproof. New cable from the battery to the starter motor and the new earth cables taken from the battery on to a main switch and then to ground on the car (beam) One to the gearbox so the starter gets all the power it requires at the startup moment.
 The main switch that we used is a 2500A in metal (do not buy them in plastic because they are not durable), they're a little expensive, but they last!
Jens had bought 4 new rear lights that we got fitted with a 7 link cable (6 × 1mm3 and 1 * 2.5 mm3 cable) from each side so all bulb has its own wiring ie. one side of the car has 2 wires Blink / brake / tail light and the last 2.5 mm3 is ground so all taillights are ground from chassis and from the cable that goes to ground in the engine compartment. Ole pulled the cables inside the beam all the way up into the engine compartment.
 Then we came to the engine compartment.
A new cable, 10mm3, was pulled from the starter motor and the amp metre into the the relay, and the amp meter on to the main consumption cable linked to the fuse box.
We made new cables with 2.5 mm3 from both headlamps, new Seal Beam 6V, and got fitted them to switch short / long, in the same Flex hose and pulled it to the lamp and position light.
Meanwhile, Ole got rid of all the old cables in the dashboard.
 Then it was the turn of the cab, if one can call it that, in an open GMC. Ignition contact and the ignition coil and fuel gauge was wired and it worked first time (fuel gauge can be tricky bit). All cables in this GMC is now hand soldered, and all cable connections are waterproof and witout any connectors or power thieves! As an added plus we mounted LED turn signals to show Jens how 6V LED can make a positive difference. A little expensive though.
A little calculation:
A backlight bulb uses about. 5-6W at 6V ie. approx. 1 A.
There are 4 of them. Furthermore, two position light. Total 6A. 6 Led bulbs will use about 0.6 A. Brake Light 21W per piece. I.e., 42-46W, and 7-8A.
Using LED as solution it will consume from 1 to 1.5 A. Indicators approx. the same as the brake light. When fitted with a LED electronic indicator light, relay
can easily make hazard warning signal, by putting a contact between R and L.
Electronic Ignition:
As icing on the cake, Jens himself installed Electronic Ignition and installed a new High Energy Ignition coil of the parts we had. This took about 15 minutes, and we think Jens is the first GMC 6V with Electronic ignition in Jutland.
Now Jens is the owner of a GMC with perfect electric networks, Electronic Ignition, new lighting, and Jens can now generate similar power on all his other cars!
This project took 2.5 days only, so Monday were used to be shown around and having a closer look at Jens' other vehicles.
A hall full of GMC, M6, Dodge and Jeeps... and being there, we obviously also traded some Jeep parts, whereafter it was time to go back to Bornholm. Unfortunately we could only get back on the 22.30 departure from Ystad, so we came home a little after midnight pretty tired. A big Thank You to Laila and Jens for their hospitality and catering. If there is some desire to know more, please contact us at flkoch@tdcadsl.dk.
Greetings, Ole Andersen and Flemming L. Koch.
Below is a very happy Jens after well done job on the GMC.
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