Unplug switch wireharness and turn fog lights on. Use DVOM to test continuity between terminal #2 and #4. Continuity should exist and when switch is turned off, there should be none.
Alternatively you can use a test lamp to ground the Red/Yellow wire to test the relay circuit. Do not unplug wireharness, backprobe the terminals taking care not to damage the terminals. If light comes on, turn switch on and backprobe the Orange/Green wire. If light comes on, switch is good and you have a fault with the DRL control unit or there is an open withe Orange/Green wire to DRL unit.
Sunday, January 16th, 2011 AT 3:43 AM