2006 ford f150 oem dvd nav problm

i bought a ford dvd navigation for my f150 and have it all installed with video and power working but no speaker sound is coming out .... can someone give me some help into why this is happening ... thank youhelp

          LIGHT GREEN/ VIOLET          (+)          RADIO HARNESS                Accesory          LIGHT GREEN/ YELLOW          (+)          RADIO HARNESS                Ground          BLACK          (-)          RADIO HARNESS                Illumination          LIGHT BLUE/RED          (+)          RADIO HARNESS                LF Speaker (+)          ORANGE / LIGHT GREEN                LF Speaker (-)          LIGHT BLUE/WHITE                RF Speaker (+)          WHITE/ LIGHT GREEN                RF Speaker (-)          DARK GREEN/ ORANGE                LR Speaker (+)          GRAY/LIGHT BLUE                LR Speaker (-)          TAN / YELLOW                RR Speaker (+)          ORANGE / RED                RR Speaker (-)          BROWN / PINK                Steering Cntrls          OPTIONAL                Speed Cntrl          YES                Radio Security          YES                            Note: makes no representation or warranty with respect to the above information including its accuracy, completeness, or its freedom from third parties' proprietary rights. disclaims all liability or responsibility for errors or omissions therein or any decision made by the recipient in reliance thereon. The installer must verify any circuitry with the proper test equipment prior to installation.       If it does not work it may have a factory amplifier