GM Service Manual Online
For 1990-2009 cars only

The following transmission-related indicators and messages may be displayed on the Instrument Panel Cluster (IPC). For a complete listing and description of all vehicle indicators and messages, refer to Indicator/Warning Message Description and Operation in Instrument Panel, Gages, and Console.

"Tow/Haul": This indicator illuminates when the PCM detects that tow/haul mode has been requested.