We have a 1999 F250 light duty model pickup. We bought this from a friend who had to sell. Hadn't needed it and husband lost the key. Needless now we need it to pull our camper and can't find the keys. ITs a tricky split year it seems?? When we call around it seems there is some discrepancy about the key being a transponder key or not. Bought non-transponder lock cylinder set, he broke PATS (I think that's what its called) piece when changing it out. Installed new PATS piece and non-transponder key lock cylinder set. (although I don't understand why it would have a security PATS thing and not a transponder key?!?) Still could not get truck to start. Theft light is on. Bought transponder KEY and thought about getting it cut to fit the newly installed cylinder. WILL THIS WORK? My husband is getting frustrated. After him being displaced for 1 1/2 years we are trying to do this as economically as possible!! Please help....

 

TLDR: call a local locksmith.

Nothing tricky about it, if it is really a LIGHT duty F250 with an F150 body, it will have PATS.
A 1999 F250 Super Duty will NOT have PATS.
Totally different body style, whole different animal.
The confusion occurs in that they called it an F250 and parts store catalogs do not make the distinction between the body styles and many of the people reading the catalogs do not know the difference.

If it does in fact have PATS*, contact a local locksmith to see if they can come to you and do it. Otherwise you will need to tow it to the locksmith and have two new keys programmed for it.
Locksmith will likely be much cheaper than a dealership. Shop around.
* With the "theft light stays on" symptom, this vehicle does have PATS. And also PATS problems, because the theft light is not supposed to stay on. This may be beyond the ability of a local locksmith.

I wanted a 3rd key for one of my trucks and asked a locksmith to cut a blank I bought. He wouldn't cut it unless I paid to have it programmed also. No price budge whether or not he programmed it. Seems like it was about $80. I have a buddy with an old school "tracer" type key cutter who cut the key for me and I programmed it myself. Total out of pocket was about $6.
Programming a 3rd key is very easy if you already have 2 working keys.

If you don't have 2 keys the PCM needs to be reset #1 to clear out the "missing keys" so no one drives off in your truck, and #2 to make room to have plenty of programming slots in the PCM. When I researched my 2003 F150 I found that it has 8 slots, meaning that a maximum of 8 keys can be programmed. This does not account for "cloning" a key which duplicates one of the codes already programmed into one of the slots. The slot #s changed for different year vehicles and different PATS versions. As far as I know, a 1999 F150 would also have 8 slots.
Deleting PATS key codes already programmed was a "dealer only" service until Ford authorized licensed locksmiths. There is also 3rd party software that allows anyone to apply for a license to Program their own PATS codes at home, but that is likely beyond the technical ability of the typical home user.
Hence the advice; call a locksmith, pay what it costs, & learn to not lose PATS keys.

Does this truck have 7 lug wheels?
Does it have this body style?

1997-2003 F150 body style
grill is 1999-2003, the earlier ones had more metal 97-98


If so, that is an F150 body regardless of what it says on the fender badge. the 97-03 F150 forum is where it fits best. That is an F150 with upgraded suspension.

1999 was the first model year for PATS on F150.
If it originally had this style of key, it has PATS.


1999 - 2003 F150 PATS key.
F ONE fifty, not Super Duty.