I have had the same fault on our BF1680 - The lights appear to come on from an over heat of the water due to no circulation of water. I found that the main circulating pump which starts after the machine fills with water was jamming up. I found the impellor is loose on the motor shaft allowing it to come into contact with the pump body which stops the pump turning - a quick check is lean the unit forward )not to far or it leak water) undo the 3 screws on the thicker base plate so it drops slightly and put a flat blade screw driver through the hole in the back onto the slot in the motor shaft - if it is any way stiff to move (i.e. it doesn't turn freely) the implellor is then catching the pump body. A replacement pump is about £80 and can be bought from most appliance spares shops or websites.
Hope this helps.
Chris Souden
September 2009