Im thinking of buying a mercedez benz c240 year of 2002, i went to go test drive it today but i noticed that when i pressed the panic button it did not do anything. I asked the seller he said he doesnt have an alarm. Does it need to have an alarm for the panic button to work? Theres a panic button on the key so i would think it should. Also, on the windows there is a sticker that says alarm, he says they are just there to scare ppl off. Is he just saying this or does it actully not work, how could i tell if he has an alarm or not, or if its not working.