Check the connection and contacts of the hazard switch. See
here if you don't know how to remove the trim to access it.
If you need an extra hazard switch to test with I have one from a pre-facelift R50 that does not fit our trim, but it is electrically compatible. Or you can hit up a local junkyard to try to find a switch and flasher relay. The hazard switch is something like $40 new, not sure about an OEM flasher relay.
There may be some other relay that controls turn signals, but I can't look it up right now (need to leave to go take an exam).