13 CASCADIA LEFT LOW BEAM INOP, COMMON KNOWN PROBLEMS?

Discussion in 'Freightliner Forum' started by ast26909, Mar 28, 2019.

  1. ast26909

    ast26909 Medium Load Member

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    H11 bulb has been replaced, left low beam still not working. I'm looking at the wiring diagram and the SAM-CAB provides 12V power to the bulb directly there is no fuse in the circuit. Any known problem areas I should check first?
     
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  3. mud23609

    mud23609 Medium Load Member

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    Yep. Check the pigtail and the wiring harness along the frame back to about the back of your steer tire. Pretty common for it to fail in that area.
     
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  4. tnevin225

    tnevin225 Road Train Member

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    Unplug the wiring harness where it comes in to the headlight assembly, thy can get corroded in there. The last one I had like that ended up costing about $1200 for a wiring harness and a headlight assembly and two dealerships just to find them. That was on a T680
     
  5. ast26909

    ast26909 Medium Load Member

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    Finally have time today to fix this problem, it turns out to be one of the pins in the bulb connector. The bulb connector looks fine at first until I start to pin test the circuits, while trying to insert a T-pin test probe next to the pins in the connector a piece of plastic around the pin broke off. I know immediately the pin was overheated and the plastic around it got brittled, break some more of the plastic around the pin and see it's all blacken.

    Autozoo as well as O'Reilly have the H11 bulb socket pigtail made by Dorman, there are 2 different parts available one with high temperature part number 84401. Two heat-shrink crimp wire connectors and it's working again, better than from the factory.

    For those who run into this problem in the future, the SAM CAB connector X18 pin 5 & 7 provide power and ground to the left low beam, pin 2 & 20 provide power and ground to the right low beam. The X18 connector is shown in the picture it's the one at the very corner of the SAB CAB underside.

    Just a rant, the cheapest 'standard' H11 bulb from either Autozoo or O'Reilly costs $16.95 on www.rockauto.com a 'standard' H11 is $3.65 as of this writing. If you drive a Cascadia you might want to buy some H11 bulbs for spare, the high and low both use H11 also don't forget a spare pigtail it seems to be a common problem.

    20190330_144850.jpg
    20190330_142811.jpg
     
  6. Dave_in_AZ

    Dave_in_AZ Road Train Member

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    Those go bad so often, my wrench buys those and the pigtails it comes with by the box lol.
     
  7. mhyn

    mhyn Road Train Member

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    Standard Motor Products HP3835 Connector/Pigtail (Body Sw & Rly) | eBay
     
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  8. Rage10

    Rage10 Bobtail Member

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    Feb 11, 2022
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    Was troubleshooting no lights on the DS and found the ground jumper to be dirty. FyI it is a capped off plug and the ground jumpers are in the green cap. So if you are looking for a bad ground, look inside those first.
     
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