I think in 2001 the computer connector is on the engine side of firewall at the top almost center, big 106 pin/wire connector.
And I think these did have a water issue with water leaking down worn out hood gasket, Ford added a cover to them.
And just as an unrelated heads up, under your drivers seat is the C340 connector that passes wires from inside the cab to underside of truck.
These would also get water inside and cause odd ball codes and problems.
Not a bad idea to service this connector before there is a problem.
read TSB here: Technical Service Bulletin 2000-2001 Ranger electrical connector - Ford Ranger Forum
But has nothing to do with OD light, that does not pass thru this connector