In the Pilot, there were numerous scenes that showed Comtron trucks...the trailers were typically white with red/orange stripes while the cabs were red with red/orange stripes. See example below:

After the Pilot, the Comtron trucks were used for the Knight Rider crew to haul filming equipment, cars, etc. On occasion, you can spot these ex-Comtron crew trailers in other episodes. I'll start you guys off with a few:
"Knight Moves" - the red cab:

"Soul Survivor" - hard to see, but I believe they are the trucks on the far right:

"Mouth of the Snake":

"Custom KITT":

"KITT the Cat":

Good luck!
Joe