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woodland_park's avatar
woodland_park
Explorer
Jun 07, 2016

1998 Atwood RV no brakelights

I'm assisting my neighbor with a brake light issue on his 1998 Atwood RV.The RV sits on a 1997 Frieghtliner frame. When pressing the brake pedal,the left and right rear brake lights do not light, but the center "cyclop" light does illuminate.This is an air brake system so the RV has to be running and up to pressure before we can start checking voltages.There appears to be 2 pneumatic switches and possibly 1 solid state switch.The rear bulbs are good. The running lights, turn signals and 4 way flashers all work.When towing a vehicle, the brake lights on it do not work either. I'm looking for a place to start troubleshooting. Thank you

7 Replies

  • dougrainer's avatar
    dougrainer
    Nomad
    Jun 16, 2016
    DrewE wrote:
    Be careful with just removing it--the diode was presumably there for some reason, probably to prevent an unwanted power feed path. Check, for example, that you don't have the third brake light flashing with the four way flashers or something along those lines.


    A DIODE is a 1 way electrical street. They are put there just as you stated---to prevent unwanted 12 volt feedback going to another circuit. The OP just needs to get a 20 amp rated Diode and install it where the original was. UNLESS, the DIODE was doing its job and by removing it the brake light power now goes where it should not go, while he has brake lights, there is power going somewhere else it should not go. Doug
  • DrewE's avatar
    DrewE
    Explorer II
    Jun 16, 2016
    Be careful with just removing it--the diode was presumably there for some reason, probably to prevent an unwanted power feed path. Check, for example, that you don't have the third brake light flashing with the four way flashers or something along those lines.
  • woodland_park's avatar
    woodland_park
    Explorer
    Jun 16, 2016
    Found the issue with the brake lights. There's a diode in one of the wire looms inside the dashboard that opened up.Had to open almost all the wire looms to find it. It ended up being located way up under the dash, behind the brake pedal, against the inside firewall. What a pain!!It also had a wrap of white label around it and if you looked closely, it said diode.I cut the diode out and spliced the wires together and we now have brake lights.Wow! Now I have to put all the wires back in place and tidy them up.
  • dougrainer's avatar
    dougrainer
    Nomad
    Jun 09, 2016
    ATWOOD RV? That is one I would like a picture of. Check the Dash steering column turn signal switch connection. Doug
  • fcooper's avatar
    fcooper
    Explorer II
    Jun 09, 2016
    Freightliner has a 24/7 help desk for freightliner chassis. These folks are good, and it is a free service.

    They will need the last 6 digits of the freightliner chassis VIN number when you call. They can look at the wiring diagram for that chassis and provide some info about where to look. They may be able to send you a copy of that chassis wiring diagram.

    Their phone is 1-800-FTL-HELP

    Fred

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