Exactly what jrd48 stated - it's just an indicator light that tells you the transfer case is in neutral. Look at the green connector on the "kit" and you will find the matching green connector under the dash near the steering column. The program may already be installed in the computer. Get an LED light ($10) and hook it up to the connector under the dash and then go through the sequence to get the transfer case in neutral. For my 2003 Explorer it was:
1. Have the vehicle connected to the motor home or otherwise secure it so it can't move.
2. With the engine running put the gear selector in neutral.
3. While the engine is running turn the key back one position so that the steering wheel is not locked - the light will flash.
4. Press on the brake and the 4X4 auto button at the same time - the light will flash about 5 times and then stay on.
5. Transfer case is now in neutral.
6. The light may go off because it works like the dome light but if you move the key forward a little without going to the start position the light should stay on. I like it like that so when I do my checks I can easily see that the vehicle is still in neutral tow.
To get it back in gear just start the vehicle normally - the light will go off.
Total cost for me was $10 - $249 is a major ripoff.