TK SB3 MAX Plus Reefer No Start

Hello all,
We've got a 03 reefer with a SB3 max that just stopped running out of the blue. Opened up the electrical box and saw that the switch was heavily corroded and replaced it with one from home depot. Issue is, according to the schematic I have the wires that the switch is connected to shouldn't be the ones that turn the reefer on and off. Theres 2AB with 12V, 8 with 0V, CH which goes to ground and one more I cant remember. The schematic I have says that 2P and 2PA are what should turn the reefer one but I dont even have a cable going to the connector body that the header connects to. Any ideas on what could be wrong?

 

Correct, no power at all actually. Took out the relay board and found the CH trace was blown, but I was able to repair that.

 

I had 12V on both power leads, not sure which is the main. All fuses are good, I've double checked them and checked the solder joints for the fuse holders to make sure they weren't cracked off. I'll check if theres a ground junction behind the battery, I have a ground stud in the electronics compartment where it seems everything ties into and that was all good. The bottom of the box has some pretty bad rust but it isn't affecting the ground from what I've tested.