When I use the turn signal or emergency lights, they won't work. All tyhe bulbs light up, just won't flash on and off.
turn signal won't work on 2003 GMC Yukon
I see a combo flasher unit for your GMC but there's a 4 pin and a 10 pin flasher available probably has to due with a tow package. Stop by a good auto parts store (Napa) and have them look at or look up which flasher your Yukon needs