It's the receiver for the Keyless Entry System.
The antenna runs up inside the passenger-side A pillar.

AL


Red '98 SVT E0 3098/6535
KKM, Elizabethan EGR Plate, TH fix
OMP front brace
Hightower rear brace
DMD
B&M with reverse lockout disabled and centering spring removed
Mobil 1 oil and trans fluid
A6 Side Markers, Optima orange, Horn recontent
Painted Sail Panels
VooDoo Knob and pedals, RogerR deadpedal
Blau Houston & CD changer
Cup holders that work
Donnelly mirror
BAT Sill Plates
and a Bullitt fuel door