2017 Tacoma will start on autostart but not push to start with fob - check charging system?

Guys I've been scouring the internet for hours, and I can't find a solution to this.

I have a 2017 Tacoma I bought from a private seller. I haven't modified anything on the truck (yet!) but he had a Compustar autostart installed.

Today, when I went to start the truck, I pressed the push to start button, the truck didn't even attempt to start. The diagnostic screen flashes "Check Charging System", then "Check Brake System". I tried to jump, no dice. I went and got a new battery (didn't mess around with testing if the old one was bad, she probably needed a new one anyway). Still no start.

Called a mechanic buddy. He asked if there was an autostart. I said yes, and tried starting the truck with that. She rips to life just fine. The normal behavior after you autostart is that the truck shuts off when you open the door. I can autostart from inside the truck, but then trying to shift out of park also shuts the truck off.

So I check fuses. On start it seems to be blowing the STOP 10A fuse, I'm trying to search the service manual for what that goes to. Assuming it has something to do with brakes! If I replace the fuse and attempt to start, it blows again.

Another factor - my dog was inside the bed, in the camper shell. Camper shell has a brake light spliced into the left rear tail light. Dog decided that wire had to go. He chewed off the wire, so I opened up the tail light and removed the (terrible) splice job. I have a hunch the issue has something to do with that. He chewed it off while I was at the gas station, and I came back to a non-starting truck (had to tow it home).

I have no idea where to go from here. Is there anything else I should attempt on my own? Do I give up and tow it to the dealership? Or tow it to the place that installed the autostart? I'm a determined man and would love to fix it myself, but I'm out of direction to go. Any tips at all would be MUCH appreciated. Thanks everyone!

 

Well, after a whole day of troubleshooting, I fixed the problem. Documenting here in case anyone else comes looking for help.

Starting the truck with the autostart did not blow the 10A STOP fuse. Attempting to start with the push to start button and brake depressed, did blow the fuse. This narrowed it down to the breaks, as I thought.
I removed the tail light the topper wires had been T spliced into, and found a very amateur job. Bad soldering, and very badly applied electrical tape.

After cutting out the ugly bits and reconnecting the wires in the tail light without splicing in the topper (that's a job for another day), I tried starting the truck via push to start and she started right up no problem.

Anyway, rock on Tacoma enthusiasts. Glad to be back on the road with mine!

 

Damn I was almost in time to tell you to check your brake pedal. Good job for finding it, im sure it was frustrating.