I don't know myself but I am in the midst of getting mine resolved. its been looked at a few times. I do know the TIPM module controls them as well. Try toggling the fog light switch. When mine does not come on (even thought it says on the dash it is). If I push it off and back on again 2-3 times they come one. The odd time it works first time.
If you're in warranty get it in!!