Off the top of my head, if I remember correctly, the "can" that surrounds the flasher is energized/hot.
There is a rubber mount that holds the can and isolates it.
The rubber mount on my 2001 EV was broken and the can of the flasher was grounding out causing a crazy flash pattern.
I taped up the can and broken mount with electrical tape and it flasher normally now.
Maybe check if the flasher is grounding out.
???
Brent