Land Rover Repair: 1996 Discovery Keyless Remote, engine controller, 9 times out of 10

Question
I have a 1996 LR Disco in which my two button remote is only working to lock the vehicle.  It doesn't work to unlock it.  Can you please tell me what I need to check?  I have a spare remote/alarm ECU that I can swap it with but before doing that, I'd like to know if I need any programming done with the remote keyless for the spare ECU for the system to work.

Answer
9 times out of 10, if one button on the remote works and the other does not, the remote is bad.

I believe the car has to be connected to the Land Rover test system to program a new remote.  You'll need a dealer or specialist for that.

DO NOT swap the alarm ECU.  If you do, the synchronization between alarm and engine controller will be lost, and you'll be towing the truck to the dealer.

The t4 or autologic tools will be needed to fix this