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# 061603.
GM WILL BE ANNOUNCING A SAFETY RECALL REGARDING UNSEALED REAR LICENSE PLATE LAMP SOCKETS THAT MAY CORRODE DUE TO WATER AND CONTAMINATES ENTERING THE REAR LICENSE PLATE LAMP ASSEMBLY. *TT