My security system came on my locked Discovery. Battery went dead, and my key will not unlock drivers door. How do I get in?

Is the remote battery dead? And why can't they unlock the car? It sounds like you got a rookie for unlocking cars! I would call another tow company, then send the bill to AAA. Unlocking the car should have nothing to do with a dead remote. I know this because I have done thousands of lockouts for a wrecker company. If the door locks are on the door their is a tool called an under over that should reach the lock or door handle. If not they can carefully wedge the door and reach them with a rod also to unlock it. Even though it's electric it should open with the manual part for safety reasons.

try unlocking and locking each door with the key to reset the security system..call the dealer and ask what the procedure to do so is. It usually involves locking or unlocking doors with the keys.
I had a vehicle once that the same thing happened to and I had to lock the driver door, then unlock and re lock with the key to reset it

Synchronization
When
Key buttons operated repeatedly while vehicle out of range and system becomes inoperative. Key batteries replaced.
How - early models
Depress lock or unlock button. Manually lock and unlock driver's door within 30 seconds. System should operate normally after approximately 1 minute. If not, carry out programming procedure.
How - late models
If vehicle locked, manually unlock driver's door using key. Press key unlock button once. Switch ignition ON and OFF. Remove key from ignition switch. Press key lock or unlock button once. System should now operate correctly.

Synchronization
When
Key buttons operated repeatedly while vehicle out of range and system becomes inoperative. Key batteries replaced.
How - early models
Depress lock or unlock button. Manually lock and unlock driver's door within 30 seconds. System should operate normally after approximately 1 minute. If not, carry out programming procedure.
How - late models
If vehicle locked, manually unlock driver's door using key. Press key unlock button once. Switch ignition ON and OFF. Remove key from ignition switch. Press key lock or unlock button once. System should now operate correctly.

Firstly, pop a new battery in the fob.
Now we can enter the EKA.
Close all the doors.
Turn the key in the driver door lock to the unlock position and hold there for at least 5 seconds until the alarm sounds once. Then return to centre - always ensure you return to centre and do not delay more than 10 seconds between turns, or hold in the position for more than 5 seconds or you will reset to the start. Turn to full extent of travel.
1st Digit turn to unlock the number of times specified.
2nd Digit turn to lock the number of times specified.
3rd Digit turn to unlock the number of times specified.
4th Digit turn to lock the number of times specified.
Finally turn to unlock once more. If it is correct a double bleep will sound (single bleep is incorrect code)
You now have a 5 minute delay - don't open any doors. The anti-theft indicator will continue flashing once every 2 seconds for the five minute period. When this goes out, open the door and start within 30secs.
After 3 failed attempts, the security system invokes a delay period of 10 mins during which the system will not accept any further attempts to enter a code.

security ----encrypted software dealer only

try to reprogram the remotes using these instructions..........
i assume for 02 explorer not th 05 frestyle listed (although similar procedure)
Remote Transmitter Programming NOTE: All remote transmitters are programmable and must be set at the same time.

1. Make sure that the anti-theft system is not armed or triggered and key code programming is not active.

1. Open the door, then press the driver door lock control switch UNLOCK button.

1. Turn the key from OFF to ON 8 times within 10 seconds, with the eighth turn ending in ON. If the program mode is sucessfully entered the doors will lock and unlock to confirm.

1. Press any button on a remote transmitter, and the doors will lock and then unlock all doors to confirm that the remote transmitter is programmed. All remote transmitters must be programmed within 20 seconds of each other. Up to four remote transmitters can be programmed to the vehicles security module each time programming mode is entered.

1. If the door locks do not respond for any remote transmitter, wait several seconds and press the button again. If the door locks still fail to respond, refer to Locks, Latches and Entry Systems — Late Build or Locks, Latches and Entry Systems — Early Build in this section.

1. NOTE: Exiting is acknowledged by locking and unlocking the doors if at least one remote transmitter has been programmed.
   Exiting the programming mode is accomplished if one of the following has occurred:
   • The key transitions to OFF.
   • 20 seconds have passed since entering programming mode or since the last remote transmitter was programmed.
   • Four remote transmitters have been programmed.

I have a 5.2L V8 Jeep Grand Cherokee and i know to reset my security system i actually have to go around to the passenger side door and lock and then unlock it again. Seems fairly odd but that's how i was told it was reset. Give it a go and lemme know!