2004 GMC Envoy Owner's Manual - Page 128

Turn and Lane Change Signals The turn signal has two upward (for right) and two downward (for left) positions. These positions allow you to signal a turn or a lane change. To signal a turn, move the lever all the way up or down. When the turn is finished, the lever will return automatically. An arrow on the instrument panel cluster will flash in the direction of the turn or lane change. As you signal a turn or a lane change, if the arrows flash more quickly than normal, a signal bulb may be burned out and other drivers won't see your turn signal. If a bulb is burned out, replace it to help avoid an accident. If the arrows don't go on at all when you signal a turn, check the fuse. See Fuses and Circuit Breakers on page 5-97 and check for burned-out bulbs. If you have a trailer towing option with added wiring for the trailer lamps, a different turn signal flasher is used. With this flasher installed, the signal indicator will flash even if a turn signal bulb is burned out. Check the front and rear turn signal lamps regularly to make sure they are working. To signal a lane change, just raise or lower the lever until the arrow starts to flash. Hold it there until you complete your lane change. The lever will return by itself when you release it. The bottom of the outside rearview mirrors may also be equipped with lane change indicators. 3-8