Low beam headlights are not fused, only high beams are fused.
Direct battery voltage (unfused) is supplied to the headlight switch at all times. When the switch in turned on, it supplies power to the ALL ACTIVITY MODULE then from the AAM power is supplied to the EXTENDED ACTIVITY MODULE and then from there power is supplied directly to the headlights.
It can't be a ground problem because each headlights' ground is at a different location. So the easiest way to check this is to remove the covers on the steering column. With the headlight switch off find the orange wire and test it with a test light. It should not illuminate the test light. Now turn on the lgiht switch on. If the orange wire does not light the test light then you need a new combination switch. If it does light you have a problem from the switch through either of the two modules.