On a 2008 Sierra you must first remove the 2 bolt on top then on the wheel well their is 2 bolt that release the lower front rap around below head light then their is a bolt that must be loosed. the light pulls out from the bottom.
The horn is located behind the left headlight. Remove the headlight pins, and then the headlight. You should be able to spot it then.
how to remove and install fenders on my 1994 gmc sierra
The 2008 GMC Sierra-2500HD has a V8 engine.
The 2008 GMC Sierra-2500HD has 16 valves.
The 2008 GMC Sierra-3500HD has 16 valves.
The 2008 GMC Sierra-3500HD has a V8 engine.
The 2008 GMC Sierra-1500 has a V6 engine.
The 2008 GMC Sierra-1500 has 12 valves.
The 2008 GMC Sierra-3500HD has overhead valves (OHV).
The 2008 GMC Sierra-2500HD has overhead valves (OHV).
The 2008 GMC Sierra-2500HD has a 6-speed automatic.
The 2008 GMC Sierra-2500HD is a gas-powered vehicle.