Ignition wiring gets hot

[Max in Mich]

Neighbor has a N/H 2120 (90's era Diesel). Intermittently, after starting, the wire from the key to the magnetic switch gets hot and has burned insulation off.
Anyone ever had this problem and where do I tell him to start looking?

 

[sotxbill]

If in one spot, the wire is nicked, damaged, corroded and has high resistance createing the heat. If in large area, the cutoff switch is shorted and drawing too much current through the wire..

if damaged or corroded wire, fix or replace wire.

if cutoff switch, replace and then repair wire as needed.

 

[Max in Mich]

(quoted from post at 16:58:28 12/16/16)
If in one spot, the wire is nicked, damaged, corroded and has high resistance createing the heat. If in large area, the cutoff switch is shorted and drawing too much current through the wire..

if damaged or corroded wire, fix or replace wire.

if cutoff switch, replace and then repair wire as needed.

sotxbill, Thanks for the lead. We'll take a look.