Where is the programmer plug on a 1990 Olds 98 located? I own a 1996 Ciera and the plug which is shorted to program the receiver is behind a panel on the left side of the trunk. I want to add the 1990 Olds to this same transmitter but I can't find the programmer plug or receiver on the 1990 Olds. I assume it's done the same way...or maybe not!

Did you ever find the receiver or the programming plug ?

Just for future posts. There is a black box transmitter behind dash above glove box. You should be able to access the transmitter by dropping the glove box door past the rubber stopper and then reaching up and feeling for a button. It is small but the only one on transmitter. When button is pressed the locks will cycle. Press lock button on each remote you want to program. I believe locks will cycle when you do this to indicate programming was successful.

Thank you (informan67) for the advice on the location of the keyless entry receiver. It was exactly where you described it. I have viewed it with inspection mirrors and so far have not found the button. I also felt around the box but could not feel a button anywhere. Is it recessed? Any hint on button location would be useful. My next trick will be to remove the box to find the button when the temperature in my barn gets above freezing unless I can locate it with mirrors or by feel. Thanks for the help so far.