We've checked all the grounds, voltage drop, does not go into 5th, charging system, new HGS from Mercedes using the VIN to order and there is no info in alldata as to the values coming into and leaving the mods. Is it possible that something is causing the controlers to fail when plugged in?

With everything we've checked it should shift into 5th but we're missing something. Anyone have a telephone number they want to give up so we can pick your brains in real time