According to the Matrix parts catalog here at
http://www.genvibe.com/images/misc/manu ... atalog.pdf on the last page, the Toyota part number for the socket is 90075-60037
I looked at mine, and one online place that has a picture that looks like the one that's in there is
https://www.lexuspartsnow.com/parts/lex ... 60037.html There may be a better or cheaper source. I am not connected with the seller, never bought that part, am not financially
liable if any of this advice goes wrong. Some of the other google results show a different picture, Probably just a wrong picture, not a wrong part
To replace would be
-buy and receive part
-open liftgate
-take out two plastic rivets holding black cover\
-take off red lens
- remove two #3 phillips screws
-carefully pry plastic housing off liftgate
(The screws expand black square pegs that fit into hatch metal, you want to pry as close to those black pegs as possible, the general plastic housing looks like it could easily break if you pry in the middle)
-disconnect the electrical connector
-remove the socket by giving it a quarter turn
at some point put a good bulb in, then put it back together in reverse order