89 mercedes 560sl radio problem

Hello, I am trying to go behind somebody and install a radio in this car. They already tried and did something weird. First of all they cut the harness that goes to the radio. There are only four wires on the harness. Another thing is that it looks like some wires from the factory alarm run to the radio as well. Any way, using what they did, I've got the radio working. Here are the problems: 1. When the lights are turned on they start flashing, I don't know if it's the factory alarm or the hazards or what. I haven't seen the hazard switch yet. 2. I'm having trouble finding the antenna wire 3. Do I need to extend the alarm wires and keep the factory radio somewhere else in the car or what? Any info would be appreciated. Thanks.

I know exacly what your going through...those cars are horrible....my sujestion run your own wires....and if you can replace that alarm with an aftermarket...Mercedes wires their cars so no one can change anything

I got it working now but I had to disable the factory alarm. As far as I can tell everything still works right, but the flashing lights have stopped. Hopefully nothing else will come up Thanks