i found this at the ford truckworld forum
How to find the Security Keyless Keypad Code on the 2002, 03, 04 & 2005 Ford Excursion, F250, F350 and how to use the Keypad functions.
When your vehicle was newly purchased from the dealer it came with a card in the owner�s manual packet that had the keypad code on it. The packet is often lost over time and as the vehicle trades owners the code to the Keyless Entry is lost. Ford Dealers wants some big money to get the code for you by plugging in their computer to retrieve the code or using the following method. There is a much easier way for you to get the code and you don�t need any tools or automotive knowledge. I�ll show you how and where to find the code and how to reset the Keyless Entry back to the factory code or your personal code number.
There are three ways to find to it. One is a lot easier than the other but less work if you have a good eye and great flashlight. There are some Excursions, F250 and F350s that have a different wiring system so the first location to look is just above the right front kick panel; the RAP module is black in color with the numbers on the front the same as the white module. If you look above the kick panel you can see it really clear without taking anything apart. If it is not at this location please follow the next step.
This part is not hard to do you will need to remove the front cover under the steering wheel that says fuse box. (It has 4 plastic screws to remove) under the dash, the five (5) digit code is on the Cream/white box behind the radio, look to the top right of the open fuse box cover through the wires. (Towards the fire wall look through where my finger is pointing). At the back firewall, look for a 5 digit code on a sticker on a cream/white box. This is not easy but if you try every angle I promise it will appear don�t forget to use a very powerful flashlight if you want to see it. The RAP module sometimes is covered by insulation making it almost impossible to see. It is located on the firewall behind the radio just below the windshield.
The second way is a more time consuming job because you have to remover the stereo and to the rear you�ll be able to see the 5 digit code very easy. This process can take 2-10 minutes.
This is a picture of the Remote Anti-theft Personality (RAP) module. This is the module you are looking for there is nothing that identifies it as the RAP module (Some RAP modules are Black in color & it could also be up side down). It is the only box in the dash with the large bold type set with five numbers on it these is the five (5) digit code you will need from the module (my numbers were 35737). Write this number down this is the factory code for your Keyless Entry.
Now that you�ve got the code I�ll tell you how to use the Keyless entry and set-up your own code.
Make sure when pressing the controls on the keyless entry keypad you press the middle of the buttons to ensure good contact with the controls.
Programming your own personal entry code
1. Enter the factory-set code (keypad will illuminate when first digit is pressed).
2. Press the 1/2 control within five seconds of step 1.
3. Enter your personal 5-digit code. Enter each digit within five seconds of the previous one.
Your personal code does not replace the factory-set code. You can use either code to unlock your vehicle. Each time you set a new personal code the module will erase the previous one in favor of the new code. The factory-set code can not be erased.
Erasing your own personal code or a prior owners code and leaving only the factory-set code
1. Enter the factory-set code.
2. Press the 1/2 control within five seconds of step one 1.
3. Press the 7/8 and 9/0 controls at the same time within five seconds of step two.
The system will now only respond to the factory-set code.
Unlocking the doors with the Keyless Entry System
1. Enter either the factory-set code or the personal code (Each digit must be pressed within five seconds of the prior digit). The interior lights will illuminate as soon as the first valid digit is pressed.
2. To unlock all the doors, enter the factory set code or a personal code and press the 3/4 control within five seconds of the drivers door unlocking.
Locking the doors wit the Keyless Entry System
1. Press 7/8 and 9/0 controls at the same time. The 5-digit code does not have to be entered to lock the doors.
Deactivating/Activating Auto-lock
1. Enter the five 5-digit code.
2. Press and hold 7/8 control.
3. Press and release 3/4 control while holding 7/8 control.
4. Release 7/8 control.
The horn will chirp once if auto-lock was deactivated