C1259 and C1310 still

Yes, it seems so. It seems many people do not press the lever down vertically in step 3 with enough force to lock it into place.

 

The (familiar once upon a time, but now less widely remembered) way that Toyota sometimes still enters part names in catalogs, with commas inserted and the principal noun moved to the front, often leads to people calling the number two frame wire a "wire frame".

There's more about how that works in other older threads. I didn't want to repeat all that here, but just remind that the thing is the number two frame wire.

 

Final update. It works! Thanks ChapmanF, punctuation and word order matter, lol. Sorry, I'm in a good mood because it works! It was indeed just the number two frame wire. So I replaced that and cleaned the other side copper plates and the couple pins in the orange ECU connector that were not quite shiny. Ultimately, I wouldn't have been able to get it right without #dolj's input with diagram. Now step 3 is proper punctuation!! Especially Brian1954 for initially responding to keep me alive here. Oh, and the AP200 is the right choice. Hopefully this thread will help others. Best to you all.