I am making a circuit to unlock my car doors. The central locking in my car works with 2 wires one at 12V, the other at 0V. When the 12V line is pulled low, the door locks. When the 0V line is pulled high, the door unlocks.
I breadboarded a circuit to let me do this ( testing circuit uses push buttons - will be replaced with remote arduino commands in future), and that works fine. I soldered up the same circuit, but when connected the doors continually lock and unlock - even when the gates on the transistors have no voltage applied. I've included a photo of the soldered perfboard (please excuse the shitty soldering) in case there is something there.
My first thought was that I had cooked the transistors, so I took another piece of perfboard and redid the whole circuit (wires were wrapped together), but I still had the same problem of it continually unlocking and locking.
This is my first time using perfboard so I am not sure whether this is an issue related to that, or something else. Any help would be much appreciated.