New headunit - now light warning buzzer no longer works

Hi guys,

have recently fitted a new Sony headunit into my fabia! looks and sounds great but one problem - it has deactivated the warning buzzer made when u leave the lights on when stopped. when i disconnect the stereo it works fine again!

anyone had this before or know how to fix it?

i really didnt think id miss that annoying beep noise - but ive left my lights on so many times without it!

Cheers

H