# 2019 F350 with Fisher XV2 plow. One headlight out.



## Kuchocki (Dec 14, 2005)

I have a plow with one headlight out. Switched to the other side of the plow, bulb works. Unplugged the plow from the truck and the opposite light on the truck went out. So I tried finding a fuse that controls it. Not listed in the manual. Google is coming up with nothing. What controls the passenger side truck light? Is there a fuse? It was so much easier when the manual told you where to look? Anybody have the wiring diagram for the 2019 F350 headlights?

Thanks.


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## cwren2472 (Aug 15, 2014)

Kuchocki said:


> I have a plow with one headlight out. Switched to the other side of the plow, bulb works. Unplugged the plow from the truck and the opposite light on the truck went out. So I tried finding a fuse that controls it. Not listed in the manual. Google is coming up with nothing. What controls the passenger side truck light? Is there a fuse? It was so much easier when the manual told you where to look? Anybody have the wiring diagram for the 2019 F350 headlights?
> 
> Thanks.


Is this new and still under warranty? If do, I'd let the dealer handle it.

If not, see if there is a piece like the photo below attached to ports b&c of the isolation module. If there is, remove it and plug the harness back in then retry the lights. It likely has that harness, doesnt need it, and its burnt out.


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## Kuchocki (Dec 14, 2005)

cwren2472 said:


> Is this new and still under warranty? If do, I'd let the dealer handle it.
> 
> If not, see if there is a piece like the photo below attached to ports b&c of the isolation module. If there is, remove it and plug the harness back in then retry the lights. It likely has that harness, doesnt need it, and its burnt out.
> 
> View attachment 200971


It's new, and wasn't sure if it was in the truck or on the plow harness. I will bypass that harness and see what happens.


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## Kuchocki (Dec 14, 2005)

I bypassed the light harness and went to the truck wiring and the light came on. So there is a short in the plow harness. Off to the plow dealer to locate the problem wire.


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## cwren2472 (Aug 15, 2014)

With the plow connected and lights on, unplug the 11 pin plow light harness. Then plug it back in. If the lights stay functional after 3 repetitions, then you don't need that relay harness and can ignore the fact that you removed it and it doesn't need to go back to the dealer (though you certainly can if you want.)


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## cwren2472 (Aug 15, 2014)

Officially all models of Ford SD from 2017-2019 are supposed to require that piece but most actually don't.


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## Kuchocki (Dec 14, 2005)

I don't have that piece. Just the long harness wired to the plow. Wish it was as simple as popping that out.


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## cwren2472 (Aug 15, 2014)

Huh? I'm confused - what did you disconnect then to get the truck lights back on?


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## Kuchocki (Dec 14, 2005)

A long harness about 6 feet long that runs along the rad to the far side of the truck where the iso module is. It has the blue connectors but it is much longer than what you have in the pic. Unless there was another connector that I couldn't see tucked behind the shrouds.


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## Western1 (Dec 4, 2008)

The harness that Cwren showed would be connected right in front of the module. Short harness


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## Western1 (Dec 4, 2008)

When you disconnected that harness did you plug truck harness back in?


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## cwren2472 (Aug 15, 2014)

I'm still confused - which of the 2 photos below does your setup look like?


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## cwren2472 (Aug 15, 2014)

From your description, it sounds like the second photo, but if that's the case, the only way you could have disconnected that and gotten the lights back on would be to totally remove the harness from the truck headlights which on that truck should have necessitated removing both of them entirely. 

(also, ignore the fact that the connectors are not fully seated in the photo)


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## timboy (Oct 8, 2008)

That is interesting information,we have been installing them on all the new quad headlight super duties and have had multiple soft start module failures.
Was this learned information or something passed on by tech support?


cwren2472 said:


> With the plow connected and lights on, unplug the 11 pin plow light harness. Then plug it back in. If the lights stay functional after 3 repetitions, then you don't need that relay harness and can ignore the fact that you removed it and it doesn't need to go back to the dealer (though you certainly can if you want.)


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## cwren2472 (Aug 15, 2014)

timboy said:


> That is interesting information,we have been installing them on all the new quad headlight super duties and have had multiple soft start module failures.
> Was this learned information or something passed on by tech support?


Learned - just our own unofficial experience


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## cwren2472 (Aug 15, 2014)

timboy said:


> That is interesting information,we have been installing them on all the new quad headlight super duties and have had multiple soft start module failures.
> Was this learned information or something passed on by tech support?


Somewhat unrelated, but we've also run into 2 or 3 vehicles that will lose a light with _or _without the soft-start - for whatever reason, those particular vehicles will work ok without the soft start so long as the headlight switch is in the "AUTO" position, but not on manual.


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## timboy (Oct 8, 2008)

Interesting,I'll have to start documenting what the particular failure was that led to the return and what setting the headlight knob is in.


cwren2472 said:


> Somewhat unrelated, but we've also run into 2 or 3 vehicles that will lose a light with _or _without the soft-start - for whatever reason, those particular vehicles will work ok without the soft start so long as the headlight switch is in the "AUTO" position, but not on manual.


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## cwren2472 (Aug 15, 2014)

timboy said:


> Interesting,I'll have to start documenting what the particular failure was that led to the return and what setting the headlight knob is in.


I might not have been clear, but those situations were ones where it was cutting out the headlight immediately after install, not ones where the soft start module had failed.


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## unhcp (Jan 20, 2010)

cwren2472 said:


> I might not have been clear, but those situations were ones where it was cutting out the headlight immediately after install, not ones where the soft start module had failed.


If you had a 19 ford that keeps killing the soft start relays, is there a fix?


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## cwren2472 (Aug 15, 2014)

unhcp said:


> If you had a 19 ford that keeps killing the soft start relays, is there a fix?


Beyond not using it, not that I know of. It hasn't happened to us yet where a truck _that required the module_ has killed one.

Our practice now is the check every truck during install as I described above to determine if the soft start module is required. In the few cases where a light goes out with or without the module, we inform the customer of the issue and explain that should they have the lights on manual, that they need to be turned off or turned back to AUTO prior to unplugging the plow. I suspect using the lights in manual is fairly uncommon anyway.


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## unhcp (Jan 20, 2010)

cwren2472 said:


> Beyond not using it, not that I know of. It hasn't happened to us yet where a truck _that required the module_ has killed one.


Truck/plow lights work fine, then after a long storm it will smell like burning and the passenger side light goes out, replace the relay in the 76272 and it works again. I was thinking maybe water got into one of the relay packs, but fisher said there was a bad batch of 76272?


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## cwren2472 (Aug 15, 2014)

unhcp said:


> Truck/plow lights work fine, then after a long storm it will smell like burning and the passenger side light goes out, replace the relay in the 76272 and it works again.


Have you tried the truck without it?



unhcp said:


> fisher said there was a bad batch of 76272?


Could be - I haven't heard of that but certainly could be possible. As I said, the only trucks we've had burn out multiple ones, just like you describe, have invariably not required the module. See my edit to my earlier response to your question.


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## Fieldspondlm (Feb 16, 2020)

Kuchocki said:


> I have a plow with one headlight out. Switched to the other side of the plow, bulb works. Unplugged the plow from the truck and the opposite light on the truck went out. So I tried finding a fuse that controls it. Not listed in the manual. Google is coming up with nothing. What controls the passenger side truck light? Is there a fuse? It was so much easier when the manual told you where to look? Anybody have the wiring diagram for the 2019 F350 headlights?
> 
> Thanks.


I would replace the 2 lighting relays in the harness. They are close to the lighting module under the hood. Fisher has a known issue with them going premature, even on a new plow with minimal use. And they fall under your 2 season warranty. The 2 relays are the same part number, so they are interchangeable. Sorry I don't have the part # with me today.....


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