foglamps

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sprinter
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foglamps

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Posted: 06.06.2022  ·  #1
One for the Brains thrust or an auto elect .
As with most EU vans, fog-lamp is on the wrong side, so I decided to fit a second one on the other side in place of the reversing light, then fit two new reversing lights, i just tandem-ed over the wiring, reversing works great.The fogs won't, only one will light initially and go out, so fit a relay with a new power feed for the bulbs and use the old wiring to power the relay.won't work,checking the power supply I have initially have 12volt.then drops to 10.85 volts, not enough to power the relay.
So before I start pulling the thing apart looking for faults, has anyone come across this,or have any idea why I'm getting the voltage drop. :-/ ?


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Re: foglamps

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Posted: 06.06.2022  ·  #2
Could it be a CANBUS issue. Perhaps the fogs are part of the CANBUS system while the reversing lights are not.

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foglamps

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Posted: 06.06.2022  ·  #3
Quote by baguette

Could it be a CANBUS issue. Perhaps the fogs are part of the CANBUS system while the reversing lights are not.


Bulbs are standard not Led.?


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Re: foglamps

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Posted: 06.06.2022  ·  #4
Quote by sprinter

Quote by baguette

Could it be a CANBUS issue. Perhaps the fogs are part of the CANBUS system while the reversing lights are not.


Bulbs are standard not Led.?


AFAIK regular incandescent bulbs can be used in CANBUS systems.

I know that, for example, adding a 12N socket to a car with a CANBUS system requires a special module, it's not just simply tapping off the loom like in pre CANBUS days.

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Re: foglamps

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Posted: 06.06.2022  ·  #5
I think Colin could well be right on this one Martin.
Canbus is intolerant of voltage drop/current draw, hence why it can “see” a bulb out.
You can switch a special solid state relay that is designed to “fool” the canbus by providing the correct resistance/draw but you also need to run a separate 12 volt supply to it and provide a ground too.
Any autofactors can supply, ask for a trailer 12n canbus relay, or if you need I keep them and will post to you.

*EDITED*
Colin beat me to it !

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Re: foglamps

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Posted: 06.06.2022  ·  #6
Does it work if you keep it to One fog and one reverse, just swapped over.


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Re: foglamps

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Posted: 07.06.2022  ·  #7
you could splice into the original fog light fit a 12 v relay 4 or 5 terminal relay 85 to ground 86 to foglight supply, 30 to red wire on your interior lamp 87 to the new foglight

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foglamps

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Posted: 07.06.2022  ·  #8
Quote by big LIam

you could splice into the original fog light fit a 12 v relay 4 or 5 terminal relay 85 to ground 86 to foglight supply, 30 to red wire on your interior lamp 87 to the new foglight


That's basically what I did 5 terminal relay 85/85 fog light wiring , new power feed to 30 lamps to the two 87,and a new ground for the lamps. didn't work. As the Lads suggest,I have a tow-bar relay winging its way to me.


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Re: foglamps

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Posted: 07.06.2022  ·  #9
Unless the van foglight is fed negative permanent + check the polarity


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on foglamps

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Posted: 19.06.2022  ·  #10
I have been away for a few days and while I initially thought the reversing lights were working ok ,I had a dash warning telling me there was a light out and the reversing camera did not operate automatically.
So following advice from Colin and Jon,( you were correct Lads :up: ) I fitted a tow-bar relay which I received in the post from another source ,(Thanks for that) , I picked up a new 12volt feed from a spare fuse that had power when the ignition is on ,and wired the new Fog and reversing light, like they were on a trailer. tested everything and had no nearside and top break light, this is a fault that has popped up now and again, two hours later, found a break in the joint where they spliced the top light into the system. I obviously disturbed the wiring, just goes to show that the saying is true. There is no such thing as a small job. :D
As suggested by Mark ,it would have been easier to just switch the lights across, but since I had bought and fitted matching light units, the CVRT man wants all light's fitted to be working.
 

 


 

next little problem is ,anyone know where i can source the little window vent covers, like this,

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Re: foglamps

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Posted: 19.06.2022  ·  #11
next little problem is ,anyone know where i can source the little window vent covers, like this,

Someone make you one with a 3D printer Martin?

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