Caterpillar320c wiring is melting

Hi, I have a Caterpillar 320c that the wiring harness, near the valve block and hydraulic pump is melting, the plastic that evolves the wire is somehow rot, never seen anything like that, I already isolated those damagem wires. First I was thinking about the cleaner liquid we used, but we used it in other machines (not Cat) with no problems. Anyone with similar problems? Old cats used to have better wiring.

Thanks

Caterpillar320c wiring is melting