V70II-optical+acoustic warning for ́n belt

good tomorrow, as probably with other mnodels I have an optical (blinking fast sign in the rear mirror frame) and acoustic (bing-bing-bing-…) warning for the installation of the safety belt. I am absolutely not a belt muffle, so always put the belt on before I go. but how do I get this “bing-bing” off switched off ? the appropriate sounder disconnect ? (where is the ?) cut the appropriate cable under the seat ? (which ) the blinking doesn’t bother me, but this bing-ton really gets on my show, if I sit in the car, the key already in the ignition lock plug but not yet immediately start. maybe someone can give me a hint ?! greetings, alex