new radio in 1989 toyota truck

Have a 1989 Toyota truck that already had a radio installed 10 years ago over the original factory installed.

I think that the person who installed that radio, cut the wires.

Am now installing a new radio for IPOD access, but the power does not work, the radio does not power up.

The 12V wire is the blue / YELLOW from the dash and should be connected to the yellow wire of new radio. These were connected, but no power. A test for power was done, and found that there was no connectivity with the blu / YELLOW wire.

 What is odd is that the old radio worked somehow. I did not take pictures of how the old was connected, so have no recourse to verify how the old radio worked.

Need advise as to how to proceed from here.