i just purchased an 05 F150 FX4 single cab, were on the truck can i find the access code for the key pad.

 

There was at time of being a new truck a plastic card about the size of a credit card in the owners manual packet. Seems like it is on a sticker in the passenger foot compartment too(at least it was in 2000). I actually wrote the code into the manual on mine when I traded it in.
You can also go by a dealer and get them to run the vin and they can get the code, unless the previous owner changed it....

 

I know nothing about the access code, just wanted to say Welcome to the site!!