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-4651A.
PONTIAC/CHEVROLET: TRAILER TURN SIGNAL AND STOP LAMPS INOPERATIVE OR STAY ON. THIS MAY HAPPEN IF THE RELAYS THAT COME WITH THE ACCESSORY TRAILER HITCH ARE INSTALLED INCORRECTLY. *PE