The first two pictures below are the original scanner, which we see about 50% of the time in the pilot, this is because these scenes were part of the presentation made by Glen Larson and his crew to NBC/Universal. Once they got the greenlight for a full series they filmed the rest of the pilot with the newer version of KITT.
Original scanner:
(note the nose of the car, it's basically the normal Trans-Am nose with a hole cut out for the scanner bar)
(the original scanner's light was also different, as can be seen here it resembles more of a long complete light that moved back and forth)
These two pictures show the scanner used for the rest of the pilot and the series itself:
(the scanner's light is now clearly made up of eight individual lights. Whereas the original scanner could also have had these, it's now much clearer)
(here you can see the nose has now been fully customised to give KITT his unique front end)
In the third series the scanner light changed slightly again, the lights were a little dimmer and the way it "scanned" changed slightly too - it no longer seemed to "slow down" (or "gather") at either end of the scanner bar as much as it did in the first two years, a shame really because I liked that effect.
Hope these helped
