Re: camshaft connector replacement
Welcome to the garage.
Strange that the wiring started to melt, there should be a fuse to protect the circuit.
Donīt know which engine you have, but Rockauto.com has connector repair kits for many of the connectors. I saw that they have connectors for the crank and cam sensors for both 4.0 and 4.7.
The oil pressure sending unit gets 5V from the PCM and this 5V is also used to feed the crank and cam sensors, the MAP and TPS. So when one of the components shorts out, the 5V is lost and the engine will not start.
Still strange though that the new sensor seems to have an internal short.