When you say "they don't work", do you mean that they stay lit but don't flash? OR, don't they light at all? If they light,but don't flash, the probable cause is a defective "flasher can" which is a little silver can about an 1 3/4" in diameter and located under the dash NEAR or clamped near the steering column. If you look at the fuse panel, you should see one there....that's the one for the emergency flashers, but they look identical. It may take a flashlight and a little "contortion" work to locate under the dash, but once you locate it, just umplug it from the harness and buy one at any auto parts store. I just replaced mine, of course when it was 10 degrees outside and me half laying outside the car trying to look up into the dash.They cost about 3.50 or so.