How to Replace Your Turn Signal Relay in a GMC Sierraby Contributor
Truck lighting systems are easy to work on, mainly because of the generous room available in the cab. You have room to move and turn around. Turn signal lights either work until they blow out or their flashers burn out. The GMC Sierra places the flashers and some fuses in the triangular plate on the end of the dash.
Check the turn signal lights for bad bulbs. Replace any bulbs that are bad. Take the cover off the fuse box and locate the fuses that control the turn signal lights. Replace any bad fuses.
Find the access panel on the driver's end of the dash. The cover plate is triangular and underneath it are a set of flashers. Behind the fuse block is where the turn signal flashers are located.
Identify which flasher is for the turn signals. Touch the surface of the flasher and then turn on the turn signal. Feel for the mechanical click that is made when the flasher blinks. This flasher controls the turn signals. Remove the flasher and replace it with a new one.
Reattach the fuse block to the inside of the hole on the end of the dash. Screw the triangular plate back on the end of the dash. Start the truck and check all the turn signal lights. Turn them on and go around the Sierra to make sure that they all light.