I have a 2002 f350 that I have changed relays, control unit, checked fuses with no change. The hazards work normally. I’m ready to drive it off a cliff. I was told that it could be a bad ground. But no one can tell me where the ground may be. I have looked at the wire run from back to front with no problems found.
Make sure you know which is ground and which is not, then run a temporary wire from a non-functioning part to the ground post of the battery. I might be a good idea to not connect things at first, use a meter to check it first.