If you have these problems，maybe you need to change Relay：

1. When turning the turn signal light to the left or right, the left and right turn lights flash simultaneously

2. The left (right) turn signal does not flash

3. When the left (right) turn signal is turned on, the danger light (double flash) also flash

This Flasher Relay Fits:

2003-2007 Hummer H2

2003 Cadillac Escalade

2003 Chevy Avalanche 1500 2500

2003 Chevy Silverado 1500 and 1500 HD

2003 Chevy Silverado 2500 and 2500 HD

2003 Chevy Silverado 3500

2003 Chevy Suburban 1500 2500

2006 Chevy Suburban 1500

2003 2005 2006 Chevy Tahoe

2003 GMC Sierra 1500 and 1500 HD

2003 GMC Sierra 2500

2003 2004 GMC Sierra 2500 HD

2003 2004 2006 GMC Sierra 3500

2003 GMC Yukon

2003 2004 GMC Yukon XL 1500

2003 GMC Yukon XL 2500