There's no easy one-stop solution since it can vary widely.
I would look at subreddits (yuck, reddit!), or dedicated forums for your model if they exist, you'd probably be surprised what's out there. (Example, there's Piloteers (Honda Pilot), Kia-Forums (Kia), 4Runners and Toyota-4Runner, etc. But information may be scattered.
First objective is figuring out if it's even on your vehicle or applicable. Older 3G radios are done since the networks that connected to them are gone now. My '16 Kia had no cellular radio. Maybe you have an SOS button or they advertise a phone app to control your vehicle remotely?
Edit: And if you can't find specific model/year information for your vehicle, you can look for information for related vehicles and see if it's relevant. Ex: Honda Passport, Pilot, Ridgeline sharing a lot of engineering.