bad light socket or bad wire to the socket, the lamp is a two element lamp which means the parking lights do not use the same element as turn signal thats why the parking lights work and the turn signal dont.
get a test light and see if you have power to the light socket, when you look into the socket you will see two small metal strips at the bottom make sure you have power there with the test light. one strip is for parking lights and the other is for turn signal. make sure the lamp is put in the right way. the little tits on the side of the lamp are stagered so it should only go in one way.
If you need more help send me an e-mail at
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Wade