It is usually under the dash either on the driver side or the passenger side. I think on those years it could be more toward the passenger side.

 

It's under the dash where your passenger's knee would be.

 

Is this a light duty F250(F150 body, 7 lug wheels?) Or a Heavy duty(92-96 F150 body style, over 8600lb GVWR, 5.8, 7.5 or 7.3L engine) If it's the second, it's entirely possible that it is OBD-1

 

If its mass air, its OBD-II

 

1996 and newer is OBDII

 

My 1997 F250 HD with a 460 is OBD-1 and the connector is located on the driverside fenderwall in the engine compartment right next to the cruise contol module. It is trapeziodal in shape and usually has a cover to protect the terminals. You can jumper 2 of the terminals and count the check engine light blinks when you do a key on engine off check.

Look here:
http://fordfuelinjection.com/?p=13

 

it is under the hood drivers side between the bat and the master but that is only if this is a 92-97 body style 250 not the LD style, the 5.0 5.8 and 7.5

 

My 1997 F250 HD with a 460 is OBD-1 and the connector is located on the driverside fenderwall in the engine compartment right next to the cruise contol module. It is trapeziodal in shape and usually has a cover to protect the terminals. You can jumper 2 of the terminals and count the check engine light blinks when you do a key on engine off check.

Look here:
http://fordfuelinjection.com/?p=13

Is your truck mass air, or speed density?

 

It was a federal mandate that if an automotive manufacturer wanted to sell a vehicle in the United States starting with the 1996 model year, then it had to be OBD-II. All vehicles sold in the United States starting with the 1996 model year are OBD-II. Ford did use a diagnostic connector in the engine compartment, but that is for doing tests with the Ford scanners or the top end scanners the jobbers sell (Snap-On, Mac, Matco). You can read the codes with the inexpensive scanners you can purchase from the parts stores, but that’s all, read only. For the 96 (97 HD) body Ford Trucks, the Assembly Line Diagnostic Link (OBD-II) connector is somewhat hidden under the dash just to the left of center.

 

My truck is SD.

I spend hours looking under the dash and see no connector. I just plug in a cheapy reader under the hood and count the blinks.