UPDATE: As of 3/22/17 the S6 Edge and S7 work fine after recent updates for the wireless charging. If you continue to experience a problem you are welcome to give me a call or stop in. I will try to help you the best I can on any wireless charging issues you are experiencing.
I have personally encountered problems when trying to use the wireless charge pad on a Samsung S7 phone in the 2017 models. These wireless charging pads work fine on the Samsung S6, however have intermittent issues with the S7 only. It will show a charging bolt for 5 seconds then shuts off. I did find that if I place the S7 towards the rear of the charge pad it will stay charging a little longer. The first thing I suggest you check is to make sure your phone doesn’t have a pending update, if it does, update it first and see if it resolves.
There were known issues on the Samsung S6’s after a update with them not wanting to charge on some vehicle wireless chargers and even on the pads and they had to change something to get the phones to work again. I do not see any GM bulletins on this problem as of yet, but it does look to be a phone issue, not a vehicle issue. Either way once I do know something I will update this post. Hopefully Samsung will release an update here soon to fix the issue.
In the meantime my suggestion to anyone with a Samsung S7 phone is to try to turn the phone “backwards,” and place it down and slide it against the “rear” until it hits the stop (phone faces rear of vehicle). If this doesn’t work try taking it out of any case. Also don’t assume your phone won’t charge until you CRANK the vehicle and try it, it needs to be running in order to charge.
There is a forum with a little more information and what others have tried at: