Hey guys I need some help. Car is acting really strange, I have a few things acting up..when I lock the car the horn goes off and stays on until I jump in the car and turn the key, I have a check engine light and my parking lights stay on with a noticable ringing sound coming from the rear of the engine..I tried disconnecting the battery and no luck, please someone point me in the right direction thanks

 

Do you have an aftermarket alarm?