Window Air Conditioner Shield

AC GFCI cord repair question?
A new portable and window air conditioner standard requires GFCI plugs on the cords that come with the units. The GFCI on the cord of an older unit I am working with will not work or reset. The line tests good for all 3 conductors (20 amp 115 v dedicated grounded circuit.) I have a portable GFCI that I plug in and it tests, resets and powers up fine.
So I concluded that the GFCI on the cord is bad. Within the cord the power and neutral conductors have a shielding conducting sheath around them. Should this be grounded or are there electronics here that prevents defeating the GFCI protection? Does the entire cord have to be replaced as a unit? Is there a proper repair method that is worth the effort and expense?
Hi
For the best possible advice, I highly recommend you contact your local supplier or the Manufacturer….
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