This is my first post here, and I just want to say that this site is fantastic!! In searching for an answer to my question I found answers to several other questions that I had.

I have a 2000 Monte and I love it. But it does have some problems. My headlights are not working. The daytime running lamps work, but at night I have no lights unless I hold back on the dimmer switch and keep them on bright. Even turning them on manually they still won't work. I checked the fuses and don't find any of the bad. I am wondering if the dimmer switch can break or if it's electronic or what and if that could even have anything to do with it. Am I missing checking a fuse somewhere, please help!

 

I just had this same thing happen to me in my 04 Monte.
The Multifunction Switch ... Headlights Hi~LO, Wipers, and Directionals quit working right.
I couldn't switch from high beams to low beams and every so often ... NO lights at all.

I had the luxury of an Extended Warranty Coverage. It was a near $600.00 Job ... with the Switch being the bulk of the money. The Dealer gets $480.00 for the Part; alone!
Get the Part Number and order one from GM Parts Direct.
After ...

You crawl up under the dash and test the leads to make sure that the Circuit is open at the Multifunction Switch ... I stuck straight pins in the wiring to do the Test Light troubleshooting.
Say hello to your steering column for me.
For the time I spent under my dash doing the testing ... I got to be on a first name basis with mine!

 

Wow that sounds like a lot of fun!! But I've never had any trouble switching from hi beams to low beams, and my wipers and turn signals work too. My headlights just all the sudden quit working.
Man I hope it's not that I just spent about that getting a new head gasket put on it. Any other suggestions?

 

Are the fuses and relay OK?

 

That you have your "Flash High Beams" function is what leads me to believe that you are having a problem with the Multifunction Switch. You problem so closely resembles the problem I had it makes me thing it's those Switches.
You don't have to take off the Steering Wheel to remove the Switch and test it. I managed to get mine off after taking-off the Steering Column surround by using a small Torx Bit and a small sized Combination Wrench to maneuver the Bit.
I Rigged a 9 Volt Battery to substitute as Power IN to the Switch and looked for the +9V OUT of the pins on the Mutifunction Switch. In my case the problem was chronically intermittent. Getting 9V on Flash and the Other wires for Lighting. But, as the Switch was worked to shift from High to Low Beams ... it was clear that the Switch was bad.
Initially, I tried one from a Boneyard. That one was worse than mine with NO Lights at all. So, off to the Dealership I went with my Extended Warranty which, after some negotiation, was honored to fix the Switch with a new one.

You are in between a rock and a hard place on this job, because if its not the Switch at fault ... it's the Bodywork Control Module. All the Lighting is controlled through the BCM and if it can't be reset will need to be replaced. Big bucks!

 

one other thing to check is under the hood on the pass side is a fuse box (rely) box
belive it is on the right side of it about the second row . (not sure so dont hold me to placement)

there is a rely there. I had somthing like this happen to mine and found out the relay went bad witch was not allowing the senonr on the dash to send signal to the lights for night/day use.

But with the switch you go around it to have the high beams working.

But i would also do like rick has said you need to make sure all of the pins there are in working order to make sure it is not a bad wire or something diffrent hurting ya

 

Probably is the dimmer switch. I rechecked all the fuses today and they are fine. But i have a question aboutchecking the relays. Do they have to have power on em to read anything on a meter? My dad says a fuse will carry current and check out on a meter but he's not sure about the relay. I saw what u said about the 9 volt battery, but i am just not sure how to check it out. A new dimmer switch is 300 bucks, so i would really like to check the relay before i go spend all that money for the switch. Does a relay check out the same way a fuse does, i mean if it doesn't carry any current on a meter its bad? The headlamp relay on the back side of the fuse box on the drivers side wouldn't carry current is why i am askin, thot maybe that would be a lot easier to fix than the darn switch. Thanks for all of your help, you guys are great!! Carey

 

There are two loops in a Relay. The LOW Current side that acts to Open and Close the Contacts ... and, ... the HIGH Current Side, the "Switch" that carries the High Current when the Relay is Closed.
With NO Power at the Relay it will test "Zero" because the Contacts are Open. When a Low Current is passed across the electromagnet, the Relay Closes and will then read "100" or Infinity.
You can pull the Relay and Probe its "Legs" with leads connected to a 9 Volt (Smoke detector type) Battery. If you are holding the Relay, you should hear and feel it clicking CLOSED when Low Power is applied to the right "Legs" causing the Relay to Close. At that point, when the Relay is Closed with the Low Power applied to its activating legs ... you should read Continuity across the other pair of legs. If not, the Relay is bad.

The Lighting Relay -- Part Number #19115080 is $17.10 from GM Parts Direct and is a Rectangular Plug-in Part.
I have a Brand New GM Lighting Relay I bought and will not use for my Fog Lights I'll sell you for 12-Bucks plus postage.