headlights don't work brights do?

2000 BUICK CENTURY
152,000 MILES • 3.1L • V6 • 2WD • AUTOMATIC
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WIMMS77
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I'm not sure on the liter size of the engine but it's a custom model but my issue is that my headlights won't come on when I pull the knob but the lights under the headlights do and the brights do when I pull and hold the multifunction switch I've checked the fuses and on the fuse box under my hood the bottom half of it no fuses light up when I check them with a fuse tester and 1 of the spots that is for the low beam lights won't let me put a fuse into it any ideas on how to fix it
Jan 3, 2026 at 5:06 AM
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STRAILER
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If the high beams work then the problem is not the fuse since both headlights (high and low beam) pull from the same power point, (fuse). Chances are the headlight switch itself is bad which is common when both headlamps go out but the brights work. To be sure remove the headlight switch and jump the yellow and blk/wht wires and the headlight lights should come out. Here is how to remove the switch in case you need it. Check out the images (below). Please upload an image or a short video in your response, so I can see what's going on.

Jan 3, 2026 at 9:55 AM
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WIMMS77
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just to make sure we are on the same page the brights come on when I hold the multifunction switch in otherwise they don't and the headlight switch is on the dash that I have to pull out in order to turn them on and the fuse box under the hood where there should be a 15 fuse inserted i cant put 1 in due to the space won't hold it in it just falls out but you think it's most likely the pull knob on the dash instead or the multifunction switch that doesn't keep the brights on unless I hold it in I will send some pics to you soon as I can get to it but give me your thoughts with this info until then
Jan 5, 2026 at 3:26 PM
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WIMMS77
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that's the pull knob for the headlights the mfs that turns on my brights that only stay on when I hold it in and the fuse box with a empty space for a 15 fuse for the headlights that won't hold it in
Jan 5, 2026 at 3:49 PM
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STRAILER
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I was looking again at the wiring diagrams and I see there is a headlamp relay, also there are 15 amp fuses, here they are and what they do. So, I would check the fuses and swap out the relay to see that helps, here is a guide to test of power at the fuses and a guide to test the relay.

https://www.2carpros.com/articles/how-to-use-a-test-light-circuit-tester

and

https://www.2carpros.com/articles/how-to-check-an-electrical-relay-and-wiring-control-circuit

Here is the location of the relay which is behind the glovebox. Please go over these guides and get back to us.
Jan 7, 2026 at 11:31 AM
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WIMMS77
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that's what I'm saying that in the fuse box under the hood for the headlamps there are 2 fuses that are 15 and they are in spots 32 and 36 well in 1 of those spots where the fuse should go into the box it won't grip it to hold it inside the box which is why I'm asking how I can fix that and if it alone can be the issue with the headlights not coming on at all as well as if it's related to my brights only working when I hold the multiswitch in as I drive otherwise they don't come or stay on either if they are not related do I need to change that multiswitch to fix the brights and the pull knob on the dash and the fuse box issue to fix the headlights I have used a 4/5 pin relay tester and all relays are good I didn't know about the fuse box behind the glove compartment so il look when I get home
Jan 7, 2026 at 11:39 AM
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STRAILER
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Okay, here are the fuses that run the headlamp system. They don't have numbers but names also, did someone remove the fuses and do these fuse positions have terminals? Some fuse panels have empty fuse holders fyi. Please check the relay but like I say it sounds like the switch is bad. If you do the test in my first post we should know for sure. Please let us know what happens. Check out the images (below).
Jan 8, 2026 at 8:35 AM