Headlights On When Switch in Off Position
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Headlights On When Switch in Off Position
2008 F-250 Crew Cab FX4 6.4L
I have seen others post on this. But I'm still not having any luck. My issue is a bit different than anything I have read. Here are the different scenarios:
1. If my switch is in the complete "Off" (12:00 Position) , the headlights stay ON. This even after I shut of engine, remove key. Lock it, walk away from it. Whatever I do I can not turn off the headlights.
2. One click to the Left, which is the Auto Position, everything works normal. Lights on at night, off during day. I shut engine off and after a delay they turn off, as they should. Note my fog lamps also work in this position if I choose to pull the switch to turn them on.
3. One click to the right (Parking Lights). All good. Everything normal.
4. Two clicks to the right (Manual On). Also all good. Everything normal.
5. Unplug the switch itself. This mimics # 1. Headlights stay on always.
I have read about power back feeding from faulty Daytime Running light Modules in other vehicles. From what I can gather there is no such module on this truck. There are no fuses or relays labeled as such.
I also wanted to trouble shoot to see if there is a relay that is stuck "closed". But I do not see any such relay in either fuse box labeled for headlights. Fuses 21, 22, and 23 in the passenger foot well are relay "feeds" for Fog, Park, and High Beam respectively. I was hoping to find a Low beam Feed. No such luck.
Any thoughts? What is the best way to trace where these are pulling power from?
I have seen others post on this. But I'm still not having any luck. My issue is a bit different than anything I have read. Here are the different scenarios:
1. If my switch is in the complete "Off" (12:00 Position) , the headlights stay ON. This even after I shut of engine, remove key. Lock it, walk away from it. Whatever I do I can not turn off the headlights.
2. One click to the Left, which is the Auto Position, everything works normal. Lights on at night, off during day. I shut engine off and after a delay they turn off, as they should. Note my fog lamps also work in this position if I choose to pull the switch to turn them on.
3. One click to the right (Parking Lights). All good. Everything normal.
4. Two clicks to the right (Manual On). Also all good. Everything normal.
5. Unplug the switch itself. This mimics # 1. Headlights stay on always.
I have read about power back feeding from faulty Daytime Running light Modules in other vehicles. From what I can gather there is no such module on this truck. There are no fuses or relays labeled as such.
I also wanted to trouble shoot to see if there is a relay that is stuck "closed". But I do not see any such relay in either fuse box labeled for headlights. Fuses 21, 22, and 23 in the passenger foot well are relay "feeds" for Fog, Park, and High Beam respectively. I was hoping to find a Low beam Feed. No such luck.
Any thoughts? What is the best way to trace where these are pulling power from?
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The pdf is helpful as far as figuring out how the switch operates. But how exactly to I tell if the WH-VT is going to negative? Does this involve piercing the wire? But before I even do this, did you notice I mentioned that I unplugged the switch completely? I would imagine when I do that, then all 5 of those position on your diagram would create an open circuit, including Position 2. But the lights are still on even when no plug is present.
Posting Guru
Joined: Nov 2008
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From: Oregon
Check for wires that are fused together, as in burned.
I had an old Ford van and the headlights remained on, even with the dimmer switch and headlight
switch removed from the vehicle.
2 wires were fused together under the hood.
I had an old Ford van and the headlights remained on, even with the dimmer switch and headlight
switch removed from the vehicle.
2 wires were fused together under the hood.
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Well this is even more bizarre. I got home last night to troubleshoot a little more. I don’t know exactly how to test that the WH-VT wire is actually going to negative. But I did inspect the wire and those around it. Everything is entact. No burns or damage.
What i I did do is pull fuses 7 & 8 in the passenger foot well box. These are labeled as Left & Right Headlamp (low beam). To my surprise the lights stayed ON with the switch Off.
At at this point I am thinking of buying a new switch. But I still don’t understand how the headlights are getting power if there is no fuse.
Other things i tested: I pulled fuse 21, 22, and 23. Which is Fog, Park, and highbeam relay feeds. They did indeed kill their respective functions. But low beams stayed on during all three tests.
Lastly i pulled # 48 which is a relay labeled Delayed Accesory. I did a continuity test on the 30 and 87 terminal to make such the relay was not stuck closed. It wasn’t.
Any other thoughts?
What i I did do is pull fuses 7 & 8 in the passenger foot well box. These are labeled as Left & Right Headlamp (low beam). To my surprise the lights stayed ON with the switch Off.
At at this point I am thinking of buying a new switch. But I still don’t understand how the headlights are getting power if there is no fuse.
Other things i tested: I pulled fuse 21, 22, and 23. Which is Fog, Park, and highbeam relay feeds. They did indeed kill their respective functions. But low beams stayed on during all three tests.
Lastly i pulled # 48 which is a relay labeled Delayed Accesory. I did a continuity test on the 30 and 87 terminal to make such the relay was not stuck closed. It wasn’t.
Any other thoughts?
Logistics Pro
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Are you the original owner? If not, I know you can install heavy duty headlight wiring harnesses that wire directly onto the battery to improve the light output. Maybe you have those and something’s screwy with them if that’s possible.
Just a stab in the dark.....
Just a stab in the dark.....
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Not the original owner. But it's clear that the wire harness is stock.
Looking at page 2 of the pdf that alloro posted above, it appears that power can get to the headlights via one of two paths.
1. into the Smart jnct box, through fuses 7 & 8, to the headlights, and eventually to ground to complete circuit. <or>
2. into the Smart jnct box, through fuse 23, then through a non-serviceable relay, to the headlights, and eventually to ground to complete circuit.
I guess I should have pulled 7, 8 and 23 all at the same time. Perhaps when I pulled 7 & 8, the path was going through 23 and the non-serviceable relay. When I pulled 23, it traveled through 7 & 8? Tonight I will try pulling all three at once and see what happens.
But not sure that's going to give me answers no matter what I find. I guess a question I have regarding pg 2 of the pdf is: Where is the switch in this diagram? I am trying to figure out how to combine what I am seeing on page 1 with what I am seeing on page 2.
Page 1 shows the switch, but where are the lights? Page 2 shows the lights, but where is the switch?
And where is this non-serviceable relay?
Looking at page 2 of the pdf that alloro posted above, it appears that power can get to the headlights via one of two paths.
1. into the Smart jnct box, through fuses 7 & 8, to the headlights, and eventually to ground to complete circuit. <or>
2. into the Smart jnct box, through fuse 23, then through a non-serviceable relay, to the headlights, and eventually to ground to complete circuit.
I guess I should have pulled 7, 8 and 23 all at the same time. Perhaps when I pulled 7 & 8, the path was going through 23 and the non-serviceable relay. When I pulled 23, it traveled through 7 & 8? Tonight I will try pulling all three at once and see what happens.
But not sure that's going to give me answers no matter what I find. I guess a question I have regarding pg 2 of the pdf is: Where is the switch in this diagram? I am trying to figure out how to combine what I am seeing on page 1 with what I am seeing on page 2.
Page 1 shows the switch, but where are the lights? Page 2 shows the lights, but where is the switch?
And where is this non-serviceable relay?
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5th Wheeling
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In my experience with late model fords, the non serviceable relay has always been in the same fuse box as the fuse. In your case the smart junction box
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The pdf is helpful as far as figuring out how the switch operates. But how exactly to I tell if the WH-VT is going to negative? Does this involve piercing the wire? But before I even do this, did you notice I mentioned that I unplugged the switch completely? I would imagine when I do that, then all 5 of those position on your diagram would create an open circuit, including Position 2. But the lights are still on even when no plug is present.
You can also test the switch by using the ohms setting on the meter and checking for continuity between the switch terminals 1 and 9 when the switch is in the Off position.
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Ok. That makes sense. I will run those tests tonight. If I register voltage in the off position, does that mean my switch is bad?
Also what do you make of the lights staying on when I pull the fuses?
Also what do you make of the lights staying on when I pull the fuses?
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alloro.
So I went to perform those tests last night. The leads in the factory harness plug were too tight to get an accurate reading trying to probe the leads from the back of the plug. So I removed the switch altogether, took it to my work bench and performed some ohm resistance tests.
Sure enough when i probed the pins where the ground and WH-VT wire would be attached my meter showed indeed there was no continuity when the switch was in the off position. I tested a few other pins as well in their respective switch positions everything else checked out ok. I.e. I did get continuity when probing pin 1 & 3 (YL-BL) with the switch in the manual ON position. And so forth with the other pins.
So I really think the switch is fried at the pin 9. I have a new one on the way. Should arrive Friday. Will let y’all know the outcome.
Thanks for the help.
So I went to perform those tests last night. The leads in the factory harness plug were too tight to get an accurate reading trying to probe the leads from the back of the plug. So I removed the switch altogether, took it to my work bench and performed some ohm resistance tests.
Sure enough when i probed the pins where the ground and WH-VT wire would be attached my meter showed indeed there was no continuity when the switch was in the off position. I tested a few other pins as well in their respective switch positions everything else checked out ok. I.e. I did get continuity when probing pin 1 & 3 (YL-BL) with the switch in the manual ON position. And so forth with the other pins.
So I really think the switch is fried at the pin 9. I have a new one on the way. Should arrive Friday. Will let y’all know the outcome.
Thanks for the help.
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Fleet Owner
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For safety reasons a failure of the controls turns the lights on by default so you can get it home or to a shop.
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I have a 2008 F-250 work trruck. No automatic lighs, windows or anything.
My headlights are on constantly. The only was to shut them off is to remove the fuse from the #23 position. As soon as I put the fuse back in the headlights are on. I've removed the light switch completely and they are still on. I do not believe I have the daylight running module on this truck.
Suggestions?
My headlights are on constantly. The only was to shut them off is to remove the fuse from the #23 position. As soon as I put the fuse back in the headlights are on. I've removed the light switch completely and they are still on. I do not believe I have the daylight running module on this truck.
Suggestions?
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