Punto hif wiring problems

[Ash85]

I have a 1.2 Punto mk2 ELX (2001 model with sub)
I took out my current hifi to see if the original cassette player worked, it looked like one of the plugs, a small yellow one wasn't connected so I connected it to my current hifi and the rear speakers went crazy, cracking and stuff, and the power steering light came on.
So I dont know what this is for, apparently it's for a AMP or something but it doesn't seem to work with my current hifi, but I think it worked with the punto cassette player.
Anyone know its full use and how to get it working?

 

[sunny2539]

Yup.. i got the same car.. basically. when i changed my head unit, the yelow 1 was plugged in. When i put it in my new head unit. it make some gay thumping noise.. so disconnected it and everything works fine.. just leave the yellow 1 disconnected.

 

[Ash85]

Thanks,
So I'm guessing its for the sub amp in the back (even tho the sub works without it plugged in)
Wonder why its there tho?

 

[sunny2539]

Duno.. its something the factory head unit needed..

 

[thefishdude]

the yelloe wire is nothing to do with subs. ithe connection so the onboard computer can check that you have the inputed the security code into the stereo. once you put in your own stereo that wire is not needed. just leave loose