no turn signals while engine is running

[mattn]

Strange electrical problem. When the engine is running the turn signals don't work. (I wasn't able to check the brake lights since I was alone this morning but I think they have the same problem.)

But when the engine is off, and the signal switch is engaged, the turn signal lights come on and stay on. It has always done this when I accidently leave the signals on and stop the engine. I assume this normal. At least this means the lights are getting power, bulbs are good, etc.

Anyone have an idea why the turn signals don't work while the engine is running? I checked the fuse and it's good.

Thanks,
Matt