GFI Tripping

[Clemay]

House built in CA, in 2004. 15 amp GFI in the garage that runs exterior outlets keeps tripping. Things I have tried to troubleshoot:
1) I replaced the GFI, and still trips after approx 10-15 seconds
2) Unplugged everything in all the outlets (7), and it still trips
3) Removed the GFI and direct wired the power and all the outlets downstream work without tripping the breaker at the panel
4) Reconnected the GFI, WITHOUT hooking up the load side, and it works without tripping (tells me the GFI is not the problem and the issue is downstream of GFI??)
5) checked all of the outlets downstream of GFI for moisture, and the boxes are dry.
6) Hooked the load side of the breaker back up and it trips the GFI again after 10-15 seconds.

I am at a loss for what to do next or what the problem could be. Any help is greatly appreciated.

Thanks!

 

[Megawatt]

House built in CA, in 2004. 15 amp GFI in the garage that runs exterior outlets keeps tripping. Things I have tried to troubleshoot:
1) I replaced the GFI, and still trips after approx 10-15 seconds
2) Unplugged everything in all the outlets (7), and it still trips
3) Removed the GFI and direct wired the power and all the outlets downstream work without tripping the breaker at the panel
4) Reconnected the GFI, WITHOUT hooking up the load side, and it works without tripping (tells me the GFI is not the problem and the issue is downstream of GFI??)
5) checked all of the outlets downstream of GFI for moisture, and the boxes are dry.
6) Hooked the load side of the breaker back up and it trips the GFI again after 10-15 seconds.

I am at a loss for what to do next or what the problem could be. Any help is greatly appreciated.

Thanks!

If you did everything that you said then could they possibly be a staple drove through one of the cable’s. I’m understanding that it’s one 15 amp circuit and just 1 cable in and 1 cable out and with no other neutrals involved, then I’m stumped