SB3 Max keeps Blowing Fuse 21/8F Circuit

Hi all,
This has been an ongoing issue for the past week. I've pulled every relay off the board and tested it and followed the board schematics trying to figure out what the issue is. If I pull the run relay out all is well except for the error code, but if I put it back in and flip the switch it will instantly blow the fuse. I've tried different relays, cleaning the socket, making sure there's nothing back there, but the problem still persists. Any ideas on where to look for this magic short?

 

The driver got to a TK dealer, hopefully they come up with something as easy to fix as the above and don't charge an arm and a leg.

 

Well, got it up and running today. I think the relay board has a blown trace, the run relay is always on, and when I jumped the start relay it started right up but still has the code 35, it pops back up instantly after clearing. We're going to give the dealer another shot at it with it running and see what they say.

 

Not anymore, the code 35 still persists and I still have to jump the start relay to start the engine and the high speed relay. While probing, I found that the RRP wire has 12V when the interconnect connector is disconnected, but when i plug it in i get 4v, im not sure if RRP is supposed to pulled to ground and the 4V is being caused by a floating ground somewhere?
The dealer tech cut RRP and ran the connector side to 12V hot and that made the code 35 dissappear but the run relay never energized.

 

It is one hell of a mess. Waiting on the local dealer to open and the driver to get back from delivering the load so I can tear into it. Roadside diagnostics with a load slowly creeping up in temp is not fun. I'm suspecting there might be a broken solder joint on the board. The wiring checked out but there was some corrosion in some of the connectors so I'll be filing contacts and greasing the connectors to prevent that moving forward.