[Shotimes] Keyless entry question

[R and S]

I'm trying to add keyless entry to my 89 sho.  It originally came with 
keyless entry, but the drivers door was replaced with a slo door.  I 
have a keypad from a junkyard sho.  I plugged it in, but it doesn't seem 
to work (I have the code from the original door in the paper work).  So, 
do I have a bad keypad, or is the original to only one that will work? 
 I thought the code was programmed in the cars' computer...

Rich