Hey i just installed central locking in my gf's car and wired it to her Auto-mate car alarm. Everything was all good and the doors were operating off the alarm remote so i put everything back and tried it and it didn't work. The plug had come out of the alarm so i put it back in and the locks just started cycling up and down so i pulled the plug out and smelt burning coming from the alarm box and it wouldn't work anymore??? WTF just happened? I pulled the box apart and nothing is melted.

nothing may be melted but u know theres trouble straight away when u smell that lovely smell.....can u see in the alarm on the circuit board if there is evidence of shorts (black marks) either way unless u know what ya doin your gonna have to take it to someone who can repair it/warranty maybe...but something sounds like it shorted...

Yeah i had a look this morning at the back of the circuit board and one of the tracks had seperated and wasn't making full connection. A lot of steady hand soldering fixed that and the alarm now works fine. Its just lucky i had pulled it out when i did because you can see it almost got to the diode. I worked out that the cause of the problem was the insulation on the +12V had a small cut in it causing the wires to become exposed and short the system.

Ok everythings fixed and the remote central locking works fine off the alarm keypad. When the doors lock the alarm also comes on and also the imobiliser, but when you start the car the doors automatically lock. When you turn the car back off again, they unlock. WTF would it be doing that?? Im confused

Its an anti-hijack feature. Some alarms you can program it - others you can't. Check the manual, or build a circuit to separate the doors from the alarm while the ignition is on