What I originally thought was an issue with the starter (solenoid clicks but starter doesn't turn when ignition key is turned) seems to be an issue with the big fat main wire going to the starter. There is no voltage between the end of the wire where it connects to the starter and ground, and according to the wiring diagram this wire should always be hot.

Has anyone ever changed out this wire? It seems to connect to the wiring harness so removing it might be a pain? Should I just leave the old one in place and put the new one in in parallel?

Over the last years I've had some issues with heavy corrosion at the positive contact at the battery so I assume this might be related to the wire now being bad.

Any insight is appreciated.

 

I change just about all that come through here.

You just need to run the new one so it won`t burn or rub against moving parts .

Are you sure you had a good ground when you checked things

If it is still in the wire loom it has never been changed.

 

Is it electrically connected to something in the main harness or is it simply bundled with it? I would not trust the schematic. I would strip the flexible conduit to make sure. By then, you may as well remove the stock one IF defective.

IF, and only IF, you're absolutely sure that there is nothing else electrically connected to it, fine to leave it in there. However, that would be sloppy workmanship (I would be embarrassed to admit I did it).

Quite possible. Battery acid is nasty and could cause major corrosion. That's why when I do any cable/wire near the battery, I:
(1) Use good quality lug terminal and crimp it well (Harbor Freight Hydraulic Crimper worked well),
(2) Use high-power (80-watt) soldering iron to flow solder into all voids, interface, and exposed wire (this adds sealing and positive electrical connection between crimp barrel and the wire strands, and eliminate voids within the crimp barrel that could harbor corrosion),
(3) Coat soldered area and anywhere acid could get through with liquid electrical tape, then
(4) Heat-shrink everything.

Lots of steps but leaves no doubt about the quality of my connection- as reliable as a Toyota should be, or better.
Example is my batt to alt "B" wire...