Home Forums General Discussion SOMEBODY TALK ME DOWN!!

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    I’ve been working on my rewire job (see project status pics) and I’ve hit a wall and am about to kick my neighbor’s cat.

    The wiring harness to the rear engine compartment is encased in the body and I cannot physically track each and every wire from front to back.  I’ve guessed all I can guess and cannot get things to light up.  So I’ve decided I’m starting with a blank slate.

    The spaghetti I’m working with is just too much of a squirrel’s nest.  I feel like I’m staring at a  Any suggestions on the best way to approach this? 

    Right now my plan is to buy a battery, hook it up, and work my way out from there one wire at a time.

    Most of this is venting but I really am open to any strategies or tricks anyone may have.




    OK Rockyx,  Here’s an approach:  Use a battery charger, not a battery – less damage if you err.  Hook it up where the battery would go and put it on 12vdc and slow charge settings.  There is probably a rather heavy, usually red, wire going from the engine compartment (the voltage regulator) forward.  This goes to your ampmeter.  Then go to the engine compartment and see if anything is hot.  If so what would it be (assuming the ignition switch and lights are off).  Nothing I can think of except the heavy cable to the starter motor and one rather heavy cable to the voltage regulator.  Now what’s left?  Backup light, tail light, turn signals, license plate light, stop light, a wire to the oil pressure gauge and one to oil pressure, a rather husky wire going from the alternator/generator forward to the ammeter,  a hot wire to the coil, perhaps a small wire to the voltage regulator for the little idiot light on the dash, the choke (this usually comes off the wire going to the coil), and a wire to the starter solenoid. 

    Using a test light or a voltmeter, determine which wires are hot.  If anything except the starter motor and one to the voltage regulator, assuming that the ignition is off, you have something wrong somewhere else.  
    Turn on your lights:  There should be another wire now that is hot – tail lights and license plate.  
    Turn on your blinkers one at a time and find which wire “blinks”.
    Hit the brakes and yet another should light up.  
    Turn on your ignition, the wire to the coil and perhaps the oil pressure switch should “light up” Hook them one at a time to the coil.  If the oil pressure gauge wiggles when you do this, that wire should go to the oil pressure sender under the distributor.    The other goes to the coil.  And perhaps a short pigtail off it which would be the wire to the choke.  
    You should only have a couple of wires left as mystery wires now.  One to the backup light – put the car in reverse and see which one cycles hot when you do.  
    The last (this was just a quick think that I put on this list) would be the wire to the starter solenoid.  With the ignition switch on, hit the starter button and hopefully one and only one wire will “light up”. 
    If only it were this easy.  Call me if you’d like to discuss.  This is very hard to do over the internet.  
    Paul Mossberg


    If you can read schematics, Classic Roadsters VW powered Duchess wiring diagrams are in the Download Manuals section. The schematic for the rear harness will help you decifer the wires. Or, you can use it to build a new harness.


    You can get access to the rear harness. It is not as encased as you think. If your car was built per the factory specs, the rear harness runs from the fuse block on the driver’s side fire wall, into the side panel.


    If you remove the interior side upholstery, you will see several holes along the bottom of the fiberglass side panel that provide access to the body mount bolts. Inside the side panel, you will see the wrapped harness. There are probably wiring clips holding the harness in place.



    Paul Mossberg
    Former Owner of a 1981 Classic Roadsters Ltd. Duchess (VW)
    2005 Intermeccanica Roadster

    If you own a TDr and are not in the Registry, please go to and register (you need to copy and paste the link)



    My technique would only work if under the dash is hooked up (correctly).  I understood that it was.  



    Guys, thanks for your help.

    Paul, I’ve been using the download diagram since I started.  The problem I have is that the wire color and size is not consistent with the diagram.  So if a wire (or wires) “disappears” through the body I am having trouble finding it again where it pops back up.  And, as I said, the color and size code are basically meaningless because of what I have to deal with.  I’ve found some but not all.  I’ll keep using the diagram as well as the one from the Samba site for 71 Beetles.


    Good suggestion.  This may be the ticket but it will take a lot of trial and error.   But at least it’s a good systematic approach.  AND NO, nothing was wired under the dash.  The dash was gone and all the instruments were CUT out.  Thus my angst.

    Thanks again.  And if anyone else has suggestions…I’m listening.



    Take a break.  Get out your tow bar.  Hook it up.  Pack your wife’s suitcase (I did it once – it’s a hoot). Surprise her with a true surprise vacation.  Gently place wife in truck/car and tow your TD up.  I’m free for the next two weekends before all hell breaks loose.  Private room with own A/C and 1/2 bath for free in beautiful New Bern, NC.  I absolutely refuse to be stumped by something electrical.  


     Other wires to the rear, are emergency flashers, tachometer  and oil temp if it was equiped with them.  

     George Fisher
    Dale Schumacher



    I had the same problem w/ mine and ended up making a wire w/ a 12 volt bulb in the middle and alligator clips on each end – one end to a good ground and the other to the loose wire at the rear
    or front and would just turn on switches etc, one at a time till I got it labeled. Worked for me


    More helpful information.

    Roy, if I had the time I would take you up on your offer.

    I guess I’ll just have to print a big copy of the wiring diagram, post it on the wall, and work my way through the mess one wire at a time.

    Crap.  Scooz my french

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