Sorry, the NHTSA has not posted this TSB document yet.
You can still get the detailed info from Chevrolet for this TSB. Call your local Chevrolet dealer's service department & ask for a copy of TSB# PIT-4902.
GMC/CHEVROLET: TRAILER LIGHTS INOPERATIVE AFTER INSTALLING A HITCH. THE WIRES AT THE BACK OF THE VEHICLE FOR THE TRAILER LIGHTING DO NOT HAVE ANY POWER. THIS MAY BE NOTICED AFTER INSTALLING A NEW TRAILER HITCH, ON A VEHICLE WITHOUT THE RPO V92. *PE UPDATED 3/26/10. *PE UPDATED 11/17/10. *PE
