I just bought 2 new factory GM key fobs for my 1997 Sierra. I programmed them using a paperclip inserted into the port under the dash in the 4 and 8 slots. Then hold down the 2 buttons on the remote till the lock cycles. Worked perfectly but the problem is once I program one fob and then go program the 2nd fob, the 1st fob no longer works once the 2nd fob has been programmed. I tried back and forth several times with the same results. It seems the truck will only learn one fob at a time. Is there a way to get both fobs working at the same time? Many thanks!