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A4 B7 3.0 TDI Retrofit Tow Hitch - Problems

Discussion in 'Audi S4/A4/A4 Cab (B7 Chassis)' started by 3.0 TDI Paul, Feb 1, 2013.

  1. 3.0 TDI Paul
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    3.0 TDI Paul 4th gear

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    [Feb 1, 2013]
    I’ve recently installed a tow hitch to my A4 B7 3.0 TDI (2007MY). I’ve followed the instructions however when wiring the changes to the 32 pin grey plug the car’s indicators stop working inside and out, but hazard lights work but no clicking sound can be heard in the car.

    The remote key also fails to lock/unlock the car but it can be started and driven.

    Reverting the wires in the 32 pin grey plug restores the problem, however the how electric do not work.

    Has anyone successfully retrofitted a tow hitch to an A4 B7?

    Any tips would be gratefully received.

    Paul
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  3. Chris79
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    Chris79 On my 3rd A4! RS4 next???

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    [Feb 2, 2013]
    Hi Paul

    Have you used a vehicle specific wiring harness?

    I fitted one to mine - it came with its own ecu, just interrupted 2 canbus wires under the steering wheel and away it went. I did have an issue with lights initially but I'd coded the car as if it had an Audi towbar - this wasn't required for the device I bought.

    Chris
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  4. 3.0 TDI Paul
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    3.0 TDI Paul 4th gear

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    [Feb 3, 2013]
    Sorry I did not make that clear, I have genuine Audi wiring kit for my car. Part number 8E5 055 203 G.
    It’s the wiring to the CANBUS 32 pin grey plug that I’m having the problem with.
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  5. Chris79
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    Chris79 On my 3rd A4! RS4 next???

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    [Feb 3, 2013]
    I would check the link into the car under the steering wheel - sounds like you have have a break in the circuit - cables were orange for me.

    Do you have vagcom to check for faults?
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  6. 3.0 TDI Paul
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    3.0 TDI Paul 4th gear

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    [May 26, 2013]
    Resolved the issue.

    Problem is a mistake in Audi/Westfelia instructions.

    Instruction 14: remove orange/green (CAN High), orange/brown (CAN Low) and black/red (power) from 32 pin grey plug. Insert into black 3 pin plug supplied with wiring kit. Ensure orange/green, orange/brown and black/red wires match wires from tow loom.

    Instruction 15: this is the mistake!
    Take 3 new wires from tow loom and insert back into 32 pin grey plug to replace the 3 removed from previous instruction.
    Black/red into chamber 15 as per instructions. Orange/green into 13 NOT 12 as instructed. Orange/brown into 12 NOT 13 as instructed. This is to ensure you do not cross connect the CAN High and Low wires.

    Rest of instructions are ok.

    Tow electrics work as should finally.


    Chris thanks for looking into this.

    Paul
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  7. .Jas.
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    .Jas. Member

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    [May 29, 2013]
    Paul, where did you buy it from, and have you got any photo's of it fitted?
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