Help needed -tow bar socket not working

Discussion in 'Motorhome Chat' started by Cossieg, Sep 10, 2014.

  1. Cossieg

    Cossieg Funster

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    Hi all
    Hope someone can help? Autotrail Comanche with total tow bar. Have got to France and found out that bike rack lights aren't working. Have checked all connections and all seems ok. Have tried to test with a bit of cable and a spare bulb and can't find 12v between any pin and earth, also tried another earth point. All lights on the van are working fine. Has anyone got any ideas? Strange that nothing works which would suggest loss of the earth connection?
     
  2. tonka

    tonka Funster Life Member

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    It could be the bypass relay has failed...
    Had that happen to mine recently and had to swop for a new one... Look under van and if the main wire goes to near the drivers seat then the relay may be hidden behind the plastic cover to the right of the accelarator pedal.
    If it is you can at least check that it has input power, also there should be a fuse between that and the main battery, again may be in that same area...

    Also... Check behind drivers seat as there may be a fuse box there and if like my AT 700 there is a fuse labeled towing..

    ps... Buy a multimeter. :). better than messing with a bulb and wire.. lol
     
  3. jhorsf

    jhorsf Read Only Funster

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    power supply fuse for bypass relay?
     
  4. Cossieg

    Cossieg Funster

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    Thanks both. We're probably overloaded & the first thing i've found to be missing is my multimeter! I'll try & buy something if i see a suitable shop!

    Bit if an update, there is a box underneath which has the 7 core cable going to the rear socket, a black multicore coming from the front & a single red cable. The red cable seems to go to the fuse box under the bonnet & has a 15amp fuse inline. The fuse looks ok albeit a bit crabby. Would there be a relay somewhere? Possibly in the box under the van? I've looked in the fusebox by my right knee & in the EM50 unit behind my seat
     
  5. tonka

    tonka Funster Life Member

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    It's sound like what you have found is the actual by-pass relay...
    You need to test to see if you have 12v going in..
    If you have power there, then you need to see if anything is coming out to the socket.
    You need that multimeter... Large supermarket ? If not inside they often have a car spares place attached to them.
     

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  6. tonka

    tonka Funster Life Member

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    May help.. smart-relay-wiring-diagram2.jpg
     

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  7. Jaws

    Jaws Funster Life Member

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    We had SO much trouble with just about every aspect of the tow bar we had fitted by Towtal ( quite happy to accept it may have been rotten luck as others seem happy enough ) I would check it all very carefully.
    We had:
    No spreaders in side the Alko chassis where they had drilled and bolted through so it crushed the chassis in.
    We had no cable ties holding the wiring up
    We had joints just twisted together ( though some of the joints were done using scotchlocks.. even WORSE than just twisting said wires together !!)

    I could go on but yes, do check all the wiring carefully !!
     
  8. Cossieg

    Cossieg Funster

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    Thanks for all the help particularly Tonka! Bought a multimeter today & Think we're sorted. 15amp fuse seemed ok but i think corroded and so caused an open circuit. Fuse changed and all worked except left flasher. Unplugged from socket & checked but all seemed ok so plugged back in & now all working! Bit bizarre but electrics sometimes can be! Think the relay is beside the fuse box under the bonnet so don't know why the live feed goes to the box under the van & not to the relay. Box under the van now seems to 'chirp' which i'm not sure it did before! I 'll check again in the morning before we move on!
     
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