A method for sealing an automotive lamp assembly comprising a first member having a tongue assembly and a second member having a groove adapted to receive the tongue assembly of the first member. The process comprises the following steps (i) in situ injection molding a silicone composition or thermoplastic composition onto the tongue assembly (20) and/or into the groove (9) (ii) curing the silicone composition or thermoplastic composition in place to form a gasket (21,10) which is chemically and/or physically bonded to said tongue assembly (20) and/or groove (9) and (iii) sealing the automotive assembly by mechanically engaging the first member and the second member, at least one of which has a cured in place gasket produced in accordance with steps (i) and (ii) above.