Mine is 89 and can lock all doors gas door close windows sunroof etc with the ONE button on center console but will not open all doors with dash switch,pulling up-opening one door lock post will open all the doors and boot… as for unlatching the 89 has no auto latch… I have to go out… push button on trunk and manually lift it open…
Did you 91 boot solenoid work? hear it clunk? your button will lock the trunk? and unlock it?
If you hear the solenoid clunk… then electrics are probably OK and if the solenoid locks the boot seems the connecting LINK of mechanism to LOCK seem to be working…
if your 91 was supposed to unlock and UNLATCH the trunk…assuming it did that in past?, then id suspect something is sticking. . Might be a good idea open boot… trip lock-latch CLOSED… then have someone operate the “dash button”…do this for unlocking and locking… again the 89 is normal to LOCK but not unlock and no unlatching of lock… on 89 unlatching is done manually pushing boot lid button.
If you have the original manual check in there for what normal operation is.