Strange situation.
when I lock the doors using the fob, both doors lock.
when I unlock the doors using the fob, only the driver’s side opens.
No big deal but why?

 

Welcome to the forum. Not sure of your car, but almost all GM vehicles unlock just the drivers door with one push of the fob, I believe it was built that way for the reason of security and safety. If you hit the unlock and all doors unlocked someone (stranger maybe) could jump into the passenger side. So it gives you the option of unlocking the driver door only with one push of the unlock fob or hit the unlock twice to unlock all locks. it`s just a safety option, Hope this helps.

 

My 99 is the same. Both doors lock from the Fob. Only the drivers door unlocks from the Fob. Once inside, I can open the passenger door from the switch on the drivers door.

 

Might be the way it is, it doesn't seem right but maybe. You should be able to do a jumper wire at the driver door lock switch to unlock the passenger door at the same time you unlock the driver door, should be easy to do if that`s the way you would like it to work. Just one click, both doors unlocked.

 

We've become so used to all the comforts of our late model cars. We don't even need keys anymore! Going backwards into a 20 something year old car and it seems all so ancient! Still, I love cruising in the C5. It's an amazing ride.

 

Many thanks….I could have sworn both sides unlocked but then I’m not of sound mind…lol

 

Stege1: Welcome to the forum. You might check in the settings menu to see if there's an option to unlock both doors at once. Also you could try pressing the Unlock button twice which I think on some cars unlocks the rest of the doors.