WrenchThrower4

Running into an issue with my company's c4500 duramax. Right front turn signal was replaced about a year ago, worked fine up until June. Had no power to light anymore, ended up replacing multifunction switch & it fixed the issue, until a couple weeks ago when it started acting up again. Turn signal works fine until you turn running/head lights on. What it does then confuses me. With lights on, the right turn signal indicator on the dash stays solid, then goes dim when you turn the signal on but does not flash the light itself. We drive early every morning going to jobs so it is in fact a necessity to have working with lights on. Any help would be appreciated. Note: left signal works as it should all the time.