new cd player in corsa b not working

[ALfooy]

i have posted this in the VX section, so sorry for the second post, but i want to get this sorted lol.

i've just brought a new sony CD for my corsa b, i've installed it correctly and there is power coming to the cd playrr as you can put a cd in and eject it no problem, but the display won't come and it won't actally play anything.

the power cable i've got has a male and female plug, but the old cassette player has three plugs with the third slightly bigger, one what does this do and two do i need a connector with three plugs.

any help would be grateful, cheers.

[DanielC4GP]

Been a while since I installed an after market radio but when I did it I just bought a manufacture to universal wire adapter set from Halfords. All the wires that went into the back of the old stereo fit straight into the adaptor and then the wires from the adaptor plug straight into the back of the new stereo. They were around £8 when I last bought one but you can get them cheaper off of fleebay.

[Jamirecluse]

I've got an aftermarket one fitted by the last owner of my corsa.I'd rather just have a standard one as it is hard to work and isn't picking up any radio signal.