Not enough information.
On my 1997 Discovery trying to unlock any door other than the driver's door sets off the security alarm, so I would not count on unlocking all doors from the rear door.
To open the gas tank on a Land Rover Discovery, first ensure the vehicle is in the "Off" position. Then, locate the fuel door release lever, which is usually found on the driver's side, either on the floor or integrated into the dashboard. Pull the lever to unlock the fuel door, then simply press on the fuel door to open it. After refueling, make sure to close the door securely.
To unlock the passenger doors on a 2003 Land Rover, you can use the key fob by pressing the unlock button. If the fob is unavailable, insert the key into the passenger door lock and turn it to unlock. Additionally, you can also unlock the doors from the inside using the central locking switch located on the driver's door panel.
To unlock a Land Rover Discovery, you can use the key fob by pressing the unlock button, which usually features a padlock symbol. Alternatively, if the vehicle is equipped with a keyless entry system, you can simply have the key fob in your pocket and touch the door handle to unlock it. If the key fob battery is dead, you can use the physical key hidden inside the fob to manually unlock the door. Always consult the vehicle's owner manual for specific instructions related to your model.
The only thing I can say I have spoken to Land Rover and they tell me the only thing in common between a Discovery 1 and a Discovery 2 is the rear door, no other panels are swapable.
To shut of the SLS audio alarm on a Land Rover Discovery by inserting the key into the door. You can also turn the ignition on partially and leave it in that position for 10 minutes before starting the vehicle.
Inside panel passenger side under dash by door.
This is a complicated procedure. It is best left to the professionals so take the vehicle in to your local mechanic.
it is under the hood right in the corner nearest the drivers door and it takes DOT 4 Brake fluid
See the following site http://www.rd.com/19539/article19539.html
This happened to our 1997 Discovery once, and it was the assembly inside the door that had gone bad. If you are a DIY kind of person, you can take the door apart and order the assembly and redo it yourself. A manual on your specific Land Rover will help to complete the project.
It may be that your Heater core is leakng Antifreeze. Not good.