The car is rather in poor condition, both aesthetically and mechanically. While the rest of the car is yellow, the left rear door has been replaced by a red one.
When he eventually gets fired from Davis & Main, Jimmy is forced to abandon the Mercedes and retrieves his bi-color wreck, which no one seems to have wanted to buy. ("Inflatable")
As confirmed by Peter Gould on Twitter, hotter colors are associated with crime in Better Call Saul, more particularly the red color. The unorthodox painting work of the car could suggest Jimmy's inner turmoil, the note of red brought by the door symbolizing his sometimes unscrupulous methods and his attraction to crime.
- 1998 Suzuki Esteem in Better Call Saul at IMCDb.org