I have two 83 Bronco's one has a box under drivers seat think it is a computer. This Bronco was made in 03-83. The other Bronco does not have one it was made 01-83. Now what is it exactly. Part number on it is..E2Y F-12A649-2 and at other end E2U F-12A650-B2B on the 03-83 truck.