Vauxhall Corsa and alpine stereo

[Drabod]

Hi all, i have just purchased a 1995 vauxhall corsa, and when fitting my stereo i have came across a problem. The stereo works so this is no problem, i have bought a harness adapter, so they could just slot in and it would work. However there is no power to the unit. The live wire through the adapter works and the stereo works, they just dont work together.

Any ideas guys ?

Cheers Rob