I spent $600 to upgrade the modem in my 2017. The dealer can't help to get it activated and directed me to AT&T. They want an IMEI number. The dealer has no idea where to get it so they ordered and sent me a new SIM card. There is no IMEI number on it. I suspect the number may be on the modem, maybe not. Does anyone know where I find the number? If it is on the modem, where is the modem in my car? Thanks!