I finally got around to relocating my battery from the passenger side to the driver's side, because the K&N diesel air filter I bought is fairly huge and comes off the turbo on the passenger side. So I get it done and all works great. Until the next day, when the truck just clicks when I hit the key. I had to get out and use a small screwdriver on the solenoid to start it. (The C6/Cummins adapter uses a 6.0 Ford starter, so the solenoid is on the starter) Anyway, I test the power coming from the small red/blue wire and it's only 7 volts.. OK, I figure there must be a rough spot somewhere, a bad connection, whatever, that's dropping the voltage. I start taking stuff apart in my quest to identify the source and I end up back at the ignition switch, which is putting out a perfect 12.4 volts, so I knew that red/blue wire itself was causing the voltage drop. I start testing the wire in 1-foot sections, and about every foot of wire is dropping the voltage by roughly 1 volt. I'm thinking.. what the hell is this, a resistor wire?? I guess it is now.. I ended up running a whole new wire from the solenoid, through the firewall grommet,(that was a p.i.t.a.) up through the plastic tube over the heater controls, and into the ignition switch, exactly like the stock wire was. Now the truck starts perfectly, but I don't get why the original red/blue wire suddenly started doing this, after I moved the battery and installed an air filter?? The wire looked perfect, still covered in the factory black tape and all, and there weren't any connectors in that section of wire. I've never seen this happen before. Obviously, I've solved the starting problem, but I don't like not knowing what caused the issue with the wire. Am I missing something here? Anyone else ever have a factory wire like this suddenly start causing a big voltage drop??
I hate electrical problems more than anything.

 

Damn the electric problems...do you still have the old wire? Split the coating off of it and inspect the the actual wire for corrosion. Im no electric genious so thats my best guess.

 

I can tell you EXACTLY why that wire started giving you trouble. (But cOpE! already did... sort of). You MOVED it. If you split that old wire open down the jacket I will bet dollars to doughnuts that you will find the copper strands inside have begun to corrode all the way down the inside. As long as the wire sat where it was in the truck and didn't move, the current carrying capacity of the wire was not compromised by the corrosion. However once you disturbed it, the corroded, brittle wire lost enough continuity due to broken strands that you lost voltage. You are lucky enough that you lost voltage as well (because you were dealing with a relatively small wire). I dealt with a similar problem for nearly two months because the positive battery cable had this happen and it still carried 12 volts but only about .45 amps... not nearly enough to turn the starter motor over.

 

I believe it.. And I bet the shaking from the diesel idling doesn't help those old wires, either. My truck sat for about 17 years unmoving in a garage, so there may be more surprises for me yet.

 

Indeed... sitting for that long, you could end up dealing with more brittle wires. Fortunately, the swap to the diesel has negated any worries about dry rotted engine hoses and gaskets.