Likely to be the alarm wiring if it's burnt, especially as heater matrix piping is in this area, which is where you have just been working. The whole point in an alarm/immob is to cut power to injectors, plugs, starter or fuel pump, if wires are burnt then it's a likely cause for your issue. If it's a alarm/immob take it out to get the car going again or replacing it (this time keeping alarm module inside the car)
