In the late 1990s GM and most other car companies changed the configuration of headlight circuits. Now the headlight switch provides the ground circuit instead of power. So yes there is a relay between the main switch and the dimmer.
The headlights get power from left and right 15amp fuses, and the relay and main switch provides the ground circuit. Your owner's manual should tell you which relay in the box is for headlights.
Testimonial: "When replacing the dimmer switch on the column does it have to be completely installed to be grounded or can I just hook up the wires to see if that is the problem?"
But you say there is 2nd relay, Because I wired the dimmer switch and got park lights but still no headlights
I said there is a relay between the dimmer and headlight switch. The ground circuit goes from the headlights to the dimmer, then thru the relay, then to the headlight switch. The parking lights are not connected to the dimmer.
I have replaced the obvious relay in the fuse box, are you saying that relay is in the column itself or just in the circuit.
Have you checked the headlight switch with a meter to see if it is working ? also, can you pull the turn signal switch to make the headlights "flash to pass" ?
I think I found the other Relay. It's in the inner panel of the driver side fuse box but, I cannot figure out how to get to the inner panel
I had a guy send a schematic but it doesn'r show how to get to it.
I've never changed that relay
The lights didn't stop working all at once. It was a slow process. One time they would work, the next time they wouldn't till they finally completely quit.
Stephen Have you checked the headlight switch with a meter to see if it is working ? also, can you pull the turn signal switch to make the headlights "flash to pass" ? Jan 19, 2014 That worked for a while but, not now.
For a while the flash to pass would work if you held it in place. But, even that has stopped working now.
I'm still trying to figure out how to get into the inner panel of the fuse box.
The flash to pass bypasses the relay and headlight switch. But both the dimmer and headlight switch get their ground from the same spot in the harness. You may need to go ahead and get a shop manual from Ebay to be able to trace the wiring and connections.
The shop manual would show you how the components are wired and probably give you the location of that main ground connection to the body.
Thanks for taking the time
If you get time and you know how to get to the inner panel of the fuse box let me know, There is a relay in there but, I can't find it. Thanks
After seeing what they want on ebay for a shop manual, I'll trade the car first. But, I hate to give up on something like headlights.
You can also sign on to alldata's website and pay for access to just the repair info for your car. I think its less than $50. Good Luck.
Aftert 220,000 miles do you think it's possible all the bulbs could have gone out within a week of each other
I doubt it.
Me too, just a thought. I'm brgining to think BCM
Me too, just a thought. I'm brgining to think BCM
Add a CommentI can get one of those for BOUT $65.00 BUT, i HAVE TO HAVE IT PROGRAMMED and I have no idea how much that costs.
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SOURCE: main headlights not working
Sounds like the head light relay is bad . Have you ever checked the headlight bulbs?
SOURCE: headlights won't work Chevy K-10 Pickup
With electrical problems I always look for a bad ground wire, especially on older vehicles. Look for any wire that goes to an inner fender or the engine, there maybe a faulty relay in the circuit too. good luck, Chuck
SOURCE: daytime running lights work but go out when I turn
If you have daytime running lights but when you turn on your regular headlight on they do not come on. Take the bottom of your steering column off (Two Small Screws) and look at the back of your turn/dimmer switch make sure that the light blue wire is connected. The wires will break off after years of raising and lowering your steering column.
If the fuse has blown, replace it with a new fuse (same amp rating) and
try again. If the fuse blows immediately, there is a short in the
headlight circuit that will have to be found and repaired before the
headlights will work. If the fuse does not blow and the headlights
work, problem solved (for now). There may be in intermittent short or
overload that caused the fuse to fail.
If
the fuse is okay and there is power, the next check would be to find
the headlight relay or control module. If the system uses a relay, pull
it out and shake it. If anything inside rattles, replace the relay.
Or buy another relay and plug that in to see if that restores power to
the headlights. 
The Buick Century is equipped with a
multi-switch. This switch is an all in one switch that controls your
cruise control, windshield wipers and turn signals in one switch. This
switch also controls dimming and brightening of your headlights. The
dimmer switch is simple to replace, and all you need is a phillips head
screwdriver to complete the task.
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When replacing the dimmer switch on the column does it have to be completely mounted
To be grounded
Not really. Both the dimmer switch and headlight switch have a dedicated ground wire.
But you say there is 2nd relay
Because I wired the dimmer switch and got park lights but still no headlights
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