Have a 2013 Buick Verano which I believe is similar to the Equinox. I've had two occurrences where the airbag icon lights and the dashboard instruments stopped working ( speedo, fuel, temp etc) and various service warnings start to display repetitively. I changed out the original battery and things seemed ok. Last few days its turned cold again; with light weight passenger in right front seat, the "passenger airbag " displays as inactive and the airbag warning icon on instrument panel lights up.
I'm suspicious of the connections under the passenger seat, defective seat belt switch, etc. Any suggestions?

 

The Enclave is most similar to the Chevy Traverse. It sounds to me like the passenger presence sensor in the passenger seat is going bad. This is common in many newer GM vehicles. However, you may just simply have a bad connection at the plug under the seat so check that first. Make sure there is no corrosion in the plug.

If yours is like the Equinox, the whole seat cushion must be replaced if the sensor is bad and costs several hundred dollars to replace. You can just install an aftermarket module which bypasses the seat sensor and permanently activates the front passenger airbag no matter what.