Marker lights won't turn off 387

My 06 379 peterbilt is doing the same thing. Turn on headlight switch and marker switch. When I turn them off, the marker lights stay on and the switch stays green even though it is off. If I pull the marker relay or hit the courtesy flash switch, the markers turn off. It even blows the headlight and marker fuse sometimes. Sometimes it will not blow the fuses for a few days and sometimes it will blow them as soon as I turn either switch on. Almost like the marker function on both switches are bumping into each other and blowing the fuses. I am thinking the relay for the markers is sticking on. I am going to replace all relays tomorrow and pray that fixes it.

 

Did you find out what was wrong? I am having the same issue and when I unplug my trailer lights at the back problem goes away.