300e Wiring harness removal

[Aus300e]

Hey Guys

Have recently pulled the 300e out of the shed and have noticed rats have been chewing on her wiring harness in the area behind the engine. The wiring goes through a tunnel from the ecu to the relay box. How does one get this harness out? I’m assuming I just undo every connector on the ecu side and pull it through? Just seems odd and super tight to have a small passage for wires. Is the there no way to access that passage? Need some know how. It’s an 88 300e