1995 GMC Yukon Owner's Manual - Page 148

NOTICE: If you keep driving your vehicle with this light on, after a while the emission controls won't work well, your fuel economy as as won't be as good, and your engine may not run smoothly. This could lead to costly repairs not covered by your warranty. K S This orange light will come on briefly when you are starting the engine. If the light comes on and stays on while you are driving, it could indicate a problem with your vehicle. It could be a problem with your oil pressure, coolant temperature, or some other problem. Check your various gages to see if they are in the warning zones. If they are, have your vehicle serviced right away. Daytime Running Lamps(DRL) Indicator Light 2-76