Turn signal is not working right.No codes are showing on 2004 Chevrolet Silverado 1500

When I turn on the left turn signal, both left and right signals come on. It doesn't always do it,it seems to be intermittent but I've noticed it works well for a few weeks and then acts up a few times before fixing itself. Thanks for any support.41000 miles is all my truck has on it.....

Asked by for the 2004 Chevrolet Silverado 1500