Author Topic: Fog Light Canbus Fault  (Read 48 times)

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Offlinee7navy1999

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    Fog Light Canbus Fault
    « on: 2018-08-12 20:55:53 »
    I added some aftermarket fog lights to replace my OEM BMW fog lights that were damaged by road rocks.  I knew that the new fog lights are double the intensity/brightness so I wired them in using a 12v relay from the battery.  Very similar to the way i wired the Air Horn.  My issue: Canbus show a fault but both fog lights do work properly with the fog light handle bar switch.  The OEM BMW lights draw 1.5 amps each and my new lamps are 3.3amps each.  This should not matter because the power comes from the battery through the 12v relay.  Any electrical experts want to put in your two cents?  The relay is suppose to only draw .8amps..well below the 1.5 amps that the OEM light required.  Could this be an under voltage issue wit the relay and how canbus draws information?  I was thinking of trying a different relay.  One that draws more amps and one that draws less.   

    Offlinee7navy1999

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      Re: Fog Light Canbus Fault
      « Reply #1 on: 2018-08-13 23:03:30 »
      After millions of hours of research I think this is what I need to do as a solution:  Option #1 is buy a canbus compatible system like https://www.clearwaterlights.com/pages/canopener  89usd or hex-ezcan $185usd.  Option is try to put a 10w LED load Resistor onto the handlebar switch side, might need to go with a 25w but well let you all know afterwards.  It will draw just about equal to the 13w each of the OEM BMW LED Fog Lights.  My issue is the relay I use to have the handlebar fog switch just does ot draw enough power so the canbus reports a missing or burned out light bulb.  If I wired directly to the new 40w LED Fog lamps from the handlebar OEM fog switch the canbus overloads and shuts down the power to the fog lights completely.  My theory is to put in an LED lod resistor on each Fog lamp side where the switch connects to.  When I energize the handlebar fog switch the 12v power will go through the rely and through the 10w load resistor hopefully "tricking" the canbut into seeing two perfectly good Fob Lamps at around 10-14 watts each.  In reality the relay is directly wired to the 12v battery and will power on two each super bright LED 40w lamps.  Wish me luck.  I order the load resistors from ebay @ $4usd each, arrive next week.   If it does not work I will go with the $189 ezcan system but hate myself for spending too much and taking the easy route

       

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