I have the unliited data plan with OnStar for $20/month. It's just for the Wifi only, no other services.
A few months ago, I noticed that my signal started becoming very spotty. In places I normally had good wifi strength, I wouldn't have signal at all. I've been on the phone with Onstar a half dozen times about it and we've gone through all the trouble shooting efforts as well as trying to connect on multiple devices to make sure it wasn't my phone. Then, about a month or so ago, I lost Wifi altogether. I mean, my phone (iPhone 12) couldn't even find the server anymore. Again, tried with multiple devices. Nothing.
After running several tests, OnStar recommended I take it ot the dealership for a hardaware diagnostic check. $150 bucks later, they said it seemed to be working fine (although no device could locate the network). The onboard unit was, however, finding all the other wifi networks in the area. Finally, they told me they thought it might be the communications module ($399 for the part plus another $300 for the install). I asked what if they replaced it and it didn't work? They stared at me like I had 3 heads.
Anyone else have this issue? I did buy the extended 72 month, 72,000 mile warranty when I bought the truck new from the dealership in August 2017 but it's expired (86,000 miles on the truck), so it's looking like I'll have to pay the $700 bucks unless I get any other suggestions.