Turn signals work when light are off when lights are on they don't work?

First thing to do is replace the signal flasher.. A weak, failing flasher will surely cause that!!!!.. Hint, to help locate flasher, turn key on with engine off.. Turn on signal light and listen for flasher clicking.. To see a picture of it, Google > 552 flasher..... IF that doesn't fix it, reply for more info. .. If that 'does' fix it, let others with same problem know by posting results .. That's the object here!