1995 GMC Yukon Owner's Manual - Page 146

Glow Plugs Light I f you have a diesel engine, it has a special starting system. An orange instrument panel Glow Plugs light shows that the system is functioning properly and tells you when the engine is ready to be started. For more details, see "Starting Your Diesel Engine" in the Index. Low Coolant Warning Light If' you have a diesel engine. you have a low coolant light. As a check to show you it's working, this orange light conws on for a few seconds after the ignition is turned on. If this light comes on anytime the engine is running. your system is low on coolant and the engine may overheat. See "Engine Coolant" i n the Index and have your vehicle serviced as soon as you can. 2-74