rhouseholder

I just acquired a 2011 Sierra 2500HD. I received two-four button key fobs. On the back of the fobs has the wording "PYTHON 474P". Research reveals that they are for OEM remote start feature. My guess is it was the original delivering dealer installed. The vehicle does have the remote start prep RPO. I don't think there is anything special about using it but I press "LOCK" first then the "AUX" button but nothing happens. The green lights on the fob do blink when the AUX button is pressed. Q1: How can I confirm that a remote start has been installed? Q2: Who should I seek to service it; a GM dealer, specialized automotive electrical shop or a car/truck electronics shop (BEST BUY)? Thank you in advance for any help you can offer. Randy