Indicator bleeping noise driving me mad.

What is your question?

I recently purchased a Toyota land cruiser LC5 automatic diesel, when I turn the indicators on left or right it makes an incredibly loud bleeping noise every time I use the indicators, it's a slightly different tone for the left and the right hand side. The noise is coming from underneath the passenger seat and sounds like a truck reversing. I've searched the manual and there is no indication of how to switch the sound off. How do I switch this off? What seems to make the problem better or worse? It's always the same How long have you had this problem? Been like that since I purchased the car