golf head unit

[epo]

a mate of mine has just bought a mk 2 golf gti and the standard head unit works fine but he tried to put in 3 different types of cd player each time the new cd players dont work is it just a case of the wrong iso plug

ive not even looked at it yet just thought id ask here first if anyone has any ideas

[morrie]

you can buy adaptors for the plugs. mabey wired up differently on vws.