Good Day!
My wife bought a 2004 monte 3.4. The marker/parking, running and highs all work, no lows. I replaced the switch since that's what seemed to be the most popular answer. No fix. I checked all the fuses, all good, no fix. I checked the relay on the back side of the driver side fuse block, swapped it with a known good, still not working. I checked the bulbs and they are all still intact and I removed and cleaned the headlight ground. Still no low beams. What am I missing? What's next?

 

Anyone? I've read so much on this, checked so many things I'm at a loss here.

 

Once you've checked the obvious stuff, its time to break out a multimeter and wiring diagram and start checking.

Test each accessible location (say from the bulb socket moving up stream) until you find out where the break is.

 

It is the multifunction switch. I have replaced dozens of these. I had to drive to work for a week holding the lever back in the "high beam" position.