Both Headlights suddenly stopped working
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Senior User
Joined: Mar 2009
Posts: 109
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From: Cordova, TN
Both Headlights suddenly stopped working
Well a few days ago I pulled up to a gas station on my way to work for some coffee and since I leave for work before 6:30 AM my headlights were on. Well only the running lights were working. Well I shrug it off and later that night I come to the realization that both headlights weren't working. I tried the high beams and they do work. I also pulled both bulbs and both the filaments on each bulb seemed to be intact. Any ideas as to what could cause this? I checked fuses 9 and 11 under the hood and they were both fine. I'm kinda at a loss right now.
Hotshot
Joined: Jan 2002
Posts: 17,988
Likes: 207
From: La La Land
There are no relays in your truck for low beam headlights.
About the only things it can be is the multi-function switch "pass" or "flash highs" part, or indeed the bulbs themselves.
Check the bulbs with a DVM or put them into a different truck and see.
I'm gonna guess the bulbs, even if they "looked" fine.
Pop
About the only things it can be is the multi-function switch "pass" or "flash highs" part, or indeed the bulbs themselves.
Check the bulbs with a DVM or put them into a different truck and see.
I'm gonna guess the bulbs, even if they "looked" fine.
Pop
Hotshot
Joined: Jan 2002
Posts: 17,988
Likes: 207
From: La La Land
Each beam is individually-fused, meaning both fuses have to be bad. He has the correct fuse numbers for his truck.
Fuses 9 & 11 for the headlights (low beam only) are in the under-hood fuse/relay box.
They're the two ten-amp ones, at the top of the left "small" double-row here:
http://springerpop.net/F350/images/IDMRelay.jpg
Pop
Fuses 9 & 11 for the headlights (low beam only) are in the under-hood fuse/relay box.
They're the two ten-amp ones, at the top of the left "small" double-row here:
http://springerpop.net/F350/images/IDMRelay.jpg
Pop
Thread Starter
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Senior User
Joined: Mar 2009
Posts: 109
Likes: 0
From: Cordova, TN
There are no relays in your truck for low beam headlights.
About the only things it can be is the multi-function switch "pass" or "flash highs" part, or indeed the bulbs themselves.
Check the bulbs with a DVM or put them into a different truck and see.
I'm gonna guess the bulbs, even if they "looked" fine.
Pop
About the only things it can be is the multi-function switch "pass" or "flash highs" part, or indeed the bulbs themselves.
Check the bulbs with a DVM or put them into a different truck and see.
I'm gonna guess the bulbs, even if they "looked" fine.
Pop
Checked them as stated in original post. They are good.
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Hotshot
Joined: Jan 2002
Posts: 17,988
Likes: 207
From: La La Land
MFS=Multi-Function Switch.
The reason they both blew at the same time is because that's what you THINK happened.
There was a clue in your original post that tells me you've been driving around with one headlight that you hadn't noticed. Heck, just this morning you had NO headlights and you didn't notice until you got out at the gas station and saw them both out. I suspect that one went out VERY recently, but the other has been out for at least a couple of days.
You turn them on when leaving the house, but that's not completely dark then, is it?
Well, now you know how to fix them. Go with the stock halogen bulbs and they'll last a long time.
Pop
The reason they both blew at the same time is because that's what you THINK happened.
There was a clue in your original post that tells me you've been driving around with one headlight that you hadn't noticed. Heck, just this morning you had NO headlights and you didn't notice until you got out at the gas station and saw them both out. I suspect that one went out VERY recently, but the other has been out for at least a couple of days.
You turn them on when leaving the house, but that's not completely dark then, is it?
Well, now you know how to fix them. Go with the stock halogen bulbs and they'll last a long time.
Pop
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Thread Starter
|
Senior User
Joined: Mar 2009
Posts: 109
Likes: 0
From: Cordova, TN
MFS=Multi-Function Switch.
The reason they both blew at the same time is because that's what you THINK happened.
There was a clue in your original post that tells me you've been driving around with one headlight that you hadn't noticed. Heck, just this morning you had NO headlights and you didn't notice until you got out at the gas station and saw them both out.
The reason they both blew at the same time is because that's what you THINK happened.
There was a clue in your original post that tells me you've been driving around with one headlight that you hadn't noticed. Heck, just this morning you had NO headlights and you didn't notice until you got out at the gas station and saw them both out.
EDIT: I just saw your edited post. That is really my only guess as to what happened. I've worked on cars my whole life and I can't remember ever seeing 2 go out within a couple days.
New User
Joined: Jan 2015
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Dancing around the problem
For those of you dancing around the problem on a 99-2003 F Series with low beams that quit and the DRL's still work or they come and go when you hit a pothole, your problem lies in the relay connections under the hood. I see people saying the low beams don't have relays and they most certainly do. The problem lies in the power feed to the main low beam relay box. It becomes corroded over time and loses it's connection. The fix is simple. In the following 3 photos, you will see images of 2 relay boxes. One has a center pin and one does not. The one you are after has the center pin. Flip it over, remove the cover and check/repair the center connection on the big relay. Problem solved.
Browse photos from album "F450LightRelay"
Browse photos from album "F450LightRelay"
New User
Joined: Mar 2017
Posts: 21
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Bill. Could this effect the fog lights as well? I’m chasing a problem with my lights. Keep haveing either my fog lights flicker on and off and or my headlights. I found a couple bad wiring connections and I changed out my multifunction switch and I’m still having the issue
1st Gear
Joined: Aug 2023
Posts: 1
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For those of you dancing around the problem on a 99-2003 F Series with low beams that quit and the DRL's still work or they come and go when you hit a pothole, your problem lies in the relay connections under the hood. I see people saying the low beams don't have relays and they most certainly do. The problem lies in the power feed to the main low beam relay box. It becomes corroded over time and loses it's connection. The fix is simple. In the following 3 photos, you will see images of 2 relay boxes. One has a center pin and one does not. The one you are after has the center pin. Flip it over, remove the cover and check/repair the center connection on the big relay. Problem solved.
Browse photos from album "F450LightRelay"
Browse photos from album "F450LightRelay"
could you please re upload the images. I can’t seem to find the relay location anywhere on the internet.. Ive checked the fuses inside under the dash and change the Mfs but my low beams still don’t function hopefully this helps . Thank you
1st Gear
Joined: Mar 2024
Posts: 1
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Tilt wheel was the issue
@Action4478. Dude, no kidding. Adjusted the tilt and voila, lights work as advertised. Dawned on me that my wife had driven the truck and lowered the tilt wheel. That night, no lights. The light assemblies were new. I replaced the light switch after checking the fuses. Nada. After reading the posts, I was defeated to the point where the MFS had to be the culprit. No way it could be the tilt. Sure enough, ran it back up and the truck is healed. Thanks for this input!!!!
1st Gear
Joined: Dec 2023
Posts: 1
Likes: 0
@Action4478. Dude, no kidding. Adjusted the tilt and voila, lights work as advertised. Dawned on me that my wife had driven the truck and lowered the tilt wheel. That night, no lights. The light assemblies were new. I replaced the light switch after checking the fuses. Nada. After reading the posts, I was defeated to the point where the MFS had to be the culprit. No way it could be the tilt. Sure enough, ran it back up and the truck is healed. Thanks for this input!!!!
Hey, did you place the MFS or did you just fix the wire? Was it difficult? Thanks.