1996 E320 keeps blowing the F4 fuse on the K40 relay

[Burquedoka]

Greetings everyone, thank you for the add.

My neighbors 1996 E320 engine is cutting off while driving, no studdering, just dies. I am well aware of the K40 and CPS issues, as my G500 has the same Achilles Heel and I carry a spare of each under the seats just in case. With the E320 belonging to my neighbor, the big 40 amp fuse in the F4 position was blown. I opened up the k40 and found no evidence of it needing a solder repair. I took a chance and plugged in a spare 40 amp fuse and it blew it with in a minute. Can anyone tell me what is ran off of this 40 amp fuse? Could it be a bad K40 that is blowing its own fuse, or is it possible something deeper in the car is causing it to blow?

Thank you for your help!