alrite mate i had the exact same problem the relay is in the bottom right of the fuse box and is number 21 its the indicator flasher relay. mine burnt out due to some peugot driving and a small bump (doh!) but when i looked into it someone told me that water tends to leak down into the back of the fuse box and short out the relay either burning it out or temporaily making it uselss. if you replace the relay an still no luck try taking the box out and drying it out a bit first. oh yeh this was on a 1.3 1990 but i'm posative its the same for urs!
chris