Freetronic gearbox question

[majik_thighs]

Hi guy`s
I have a 2000 Yaris with the Freetronic gearbox. Works great, I bought this as a 1st car for my sons 21st.
This is the problem:
When I turn off the ignition theres a buzzing which comes from the direction what looks like a solenoid on the right hand (passengerside) side between the engine and the battery. In the picture its just behind the brake fluid reservoir which you can see. If I take off the lid of the fuse box and remove the brown relay it stops....putting it back in it starts again but if I start the engine and then turn it off......I can then put the relay back in its place without the buzzing starting up. It has something to do with the gear selection because it wont go into gear without this relay and ive had a look at a couple of scrap cars which are manual transmission and they don't have the same relay or the (what looks like) solenoid etc.

Edit: It doesn't do this all the time.....but most of the time.

Any idea`s?

TIA.