TOPIC: More wiring problems

I had a previous thread with a discussion about an ignition switch that the previous owner had rewired incorrectly. I've taken the advice to rewire it correctly after tracing each component. Now I think I know why the PO modified things. I've started this thread because now I have a different issue.

I found that I had intermittent connectivity of the black wire between the switch and the plug. I found a spot where the black shielding around the group of individual wires was crimped and in-turn where the black wire had a break. Great! soldered it, shrink wrap and I'm good to go. Then it was intermittent again! Narrowed the break down, this time, no wear on the outside shield or the insulation of the individual black wire...weird I thought, but fixed it anyway. Found a third spot and now realize that something just isn't right. In the second and third spots the outside shielding (of the group of wires) and the insulation of the black wire were not damaged in the least. The black wire is even coiled INSIDE the other wires. There is no damage to the other wires. Below are pictures that show the wire before I pulled it apart (you can see the little "bubble" where the break is. The second picture is after I stripped the wire. I was expecting to see some kind of burn or something.

So a couple of questions, has anyone seen this issue before? I'll have to replace the entire set of wires from switch to plug, but I'm concerned that the PO did the wiring like he did because there was an alternate electrical issue causing these breaks. Could that be true?

1960 Merc 300

Merc had great engines back then but with crappy wire. Clean and shrink wrap the bad spots, cross your fingers and hope for the best. They all get like that over time, nothing you can do short of buying a new replacement harness.($$$)

or run a new wire for the black one right to the motor or tap it in closer to the plug and leave the old not in use.

I had the same problem with my 69 650. I finally just said "screw it" and redid the wiring myself. It was a pain in the ass when i was doing it, but now that its done I'm glad I went through the trouble. Not only did I have the same trouble you have, but The insulation just crumbled off many of the wires as I held them. I'd rather spend the money and save the headache and worry.

Thanks for the input guys. I'd rather have faulty wire than a faulty electronic component. Last night I did some more investigation and found that over a 4 foot section there were 5 more breaks or near breaks, so repairing this wire is out of the question.

I've been somewhat of a wire hoarder (much to my wife's dislike!) and over the years have gather a few boxes of wires, everything from computer wires, old appliance wires, house wire, automotive wire and by chance......a wiring harness! that I had totally forgotten about until I started digging.

I think all the wires on the original harness are 16 gauge. This wiring harness I dug up has 4 @ 16 gauge, 3 @ 18 gauge and 1 @ 12. I know it is not a purest solution, but do you think I can get away with combining 2 of the 18 gauge (to make one) and use the 12 gauge as one. With the 4 16 gauge wires this would give me the 6 needed wires.

I ended up using the original harness and splicing a new 16 gauge black wire from plug to switch. This will do for now. I was looking around for 6 wire 16 gauge stranded wire but most places I called only sell it in 1000 foot rolls. Now my next issue...new thread for that coming up.