I don't know how to remove the pin type retainers or fasteners

It depends on how your 1998 F-150 is equipped. Some do, some don't.
Only vehicles with a filter cover in the location shown have a Cabin Air Filter. (See picture)

Instructions To Replace Cabin Air Filter 2001 LS Things You'll Need

• Pliers Screwdriver Clean damp cloth Handheld vacuum

1. • 1

     Locate the cabin air filter container on your Lincoln LS. Looking at the engine from the front, you will find the casing on the left side against the back firewall. The cabin air filter is mounted vertically and is approximately 6 by 9 inches and about 2 inches deep.
     

   • 2

     Remove the cowling cover by pushing in the black cover pins and lightly prying the cover off with a screwdriver. Lift the filter out of the container.
     

   • 3

     Vacuum the inside of the container to remove any dust or debris. Wipe down the inside and outside of the container and lid with a clean damp cloth, then dry it off completely.
     

   • 4

     Insert the new cabin air filter into the container and check to make sure it is seated properly. Cover the container by putting the lid back on and gently pushing down to make sure the pins click into place.
     

You can see most of it under the dash up high
behind the glove box

The connectors are near the firewall in engine
compartment

Have to remove the cabin filter box to see them

The cabin air filter is located on the engine compartment firewall, passenger-side. Open the hood, stand by the right front wheel and you'll see the fasteners to remove forward of the wipers. Fastener's are removed by pushing the center in, then pulling them out. To replace. pull the center out, replace it, then push it flush to lock.

Remove left front tire

Remove plastic inner fender retainer, push pins

Fuel filter is behind splash panel

Squeeze colored fuel line retainer,to remove

Open hood
Pass side,remove push pins on wiper cover ( Black plastic grill)
Under cover,open Cabin Filter Cover

Passenger side,open hood,remove most of the push pins, holding wiper cowl grill to cross brace.
Under the plastic cover is a box with another cover, and inside the cabin filter.
They are expensive and last about 3 years
Get real dirty after two

You will break a few push pins and the dealers don't stock and they are too expensive,like $3.20 ea
Use wire ties until I find a source at auto body supply houses

To Replace: This is done with the hood opened and located at the bottom of the windshield on the passenger side.

Note: The fasteners are reusable.
Remove the right side of the cowl vent screen.
Remove the two-part pin-type retainers and separate the Velcro attachment of the rubber hinge cover to the rear outboard corner of the cowl vent screen.
Pull up the cowl vent screen to release the lower clips.
Push on the RH corner of the filter to release the clip. Release the LH clip and remove the cabin air filter.
To install, reverse the removal procedure

To Reset:

Press the STATUS control to access the System Check function, the message center will display A/C FILTER XXX% RESET FOR NEW.

Press and hold the RESET control to set to 100% , the message center will display IF NEW FILTER HOLD RESET.

After a successful reset, the message center will display A/C FILTER LIFE SET TO 100%.

It's located on the engine compartment firewall, passenger-side. Open the hood, stand by the right front wheel and you'll see the fasteners to remove forward of the wipers. Fasteners are removed by pushing the center in, then pulling them out. To replace. pull the center out, replace it, then push it flush to lock.

Good luck and hope this helps.

I can provide 2002, don't have 2003. may be similar. please rate as solveed problem if this is what you needed.

SECTION 417-01: Exterior Lighting 2002 Lincoln LS Workshop Manual
REMOVAL AND INSTALLATION Lamp Assembly —Rear Removal and Installation

1. Remove the luggage compartment door trim panel.
   1. Remove the 13 pin-type retainers.
   1. Remove the luggage compartment door trim panel.

1. Remove the rear lamp assembly.
   1. Disconnect the electrical connectors.
   1. Remove the nuts.
   1. Remove the rear lamp assembly.
   • If necessary, install new bulbs.

1. To install, reverse the removal procedure.