2017 high beams, both became dim

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Joined
Mar 14, 2017
Threads
4
Messages
51
Location
Colorado
Headlights and high beams have always been awesome on the LC, yesterday night the headlights seem to work great but the highbeams both became dim. They are coming on but it is a dim, like a flaslight with super low batteries. No after market parts have been installed, just had an oil change 200 miles ago at 100k miles. We have googled it and most say check their ground, but would this affect both sides at the same time? Any ideas?
 
Original battery? Sometimes weird things happen with a wimpy battery or poor connections at the battery terminals. Any other electrical issues?
 
I'd also investigate the battery.

Each headlight assembly has it's own ground, but they are also connected seemingly for redundancy.

Pretty hard to see how it would be a ground issue.

Screenshot 2026-07-11 at 1.15.20 PM.webp
 
Original battery? Sometimes weird things happen with a wimpy battery or poor connections at the battery terminals. Any other electrical issues?
Battery is two years old, starts and runs all accessories no issue.
 
I'd also investigate the battery.

Each headlight assembly has it's own ground, but they are also connected seemingly for redundancy.

Pretty hard to see how it would be a ground issue.

View attachment 4174774
Ok, still checking it out. Going to do more later as it cools, 104 outside. Voltage drops etc.
are relays a factor with these?
 
Ok, still checking it out. Going to do more later as it cools, 104 outside. Voltage drops etc.
are relays a factor with these?

Ah yeah, I shouldn't have cropped it down so much.

Appears there are separate fuses and relays for high and low beams.

Screenshot 2026-07-11 at 7.12.55 PM.webp
 
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