Vw diagnostic connector wiring

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Lingwendil
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Vw diagnostic connector wiring

Post by Lingwendil » Fri Mar 25, 2016 11:08 pm

I'm looking to remove the diagnostic connector and is associated wiring from my 73 super beetle. I'm just having a hard time finding the origin of all the wires! Is there a central point in which they all splice in, so that I can cut them out neatly leaving as little behind as possible?

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Piledriver
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Re: Vw diagnostic connector wiring

Post by Piledriver » Fri Mar 25, 2016 11:56 pm

They are spread out through the entire harness.

I'd keep at least most of it intact as spare wires can come in very handy.
Perhaps disconnect and tie off out of sight.
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Marc
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Re: Vw diagnostic connector wiring

Post by Marc » Sun Mar 27, 2016 1:29 am

I appreciate your wanting to clean up the looks of the firewall, but do think about it first.
On the Bentley Manual schematics they don't display the diagnostic wires, just an orange dot where each one originates with the number of its terminal in the firewall plug. As Piledriver mentioned, several of them transit the firewall so they're good spots to tie in gauge wiring, etc. so you don't have to make extra holes or fish wires through.
I've never tried it, but I imagine if you have the "Term 50" diagnostic wire going to the solenoid you could use that and the "+" terminal for cranking the engine from in back...there's even one that goes to Term 15 on the coil that can be used for hotwiring if the ignition switch dies, and one from Term 1 that could be used for a sneaky anti-theft switch (ground it and there'll be no spark, even when there's power to the coil)...put a jumper wire from that one to one of the ones that go to the battery area, and splice onto it for your tachometer.

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Lingwendil
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Re: Vw diagnostic connector wiring

Post by Lingwendil » Mon Mar 28, 2016 1:48 pm

Hmmmm. I might just zip tie it off and out of the way. A couple of the wires (like to the starter for instance) are missing but I might tie into it for some things. Time to yank my back seat bottom and poke around. I was going to run a bundle of wires up front for future use, and throw an additional battery line to the dash anyway (for highlights, amp, etc)

Would be nice to rig a plug for it for working on timing and such, too bad these things went the way of the dodo...

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kangaboy
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Re: Vw diagnostic connector wiring

Post by kangaboy » Tue Mar 29, 2016 7:58 am

I just cut that thing off a few weeks ago. It's just getting in the way of my EFI system now, and it was able to provide a few spare lines from the engine bay to under the back seat. I literally never even thought of using it. Just cut all the wires flush and tuck them away in the engine bay, just in case you need them at a later date.

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Marc
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Re: Vw diagnostic connector wiring

Post by Marc » Tue Mar 29, 2016 11:38 pm

kangaboy wrote:...Just cut all the wires flush and tuck them away in the engine bay, just in case you need them at a later date.
Bear in mind that the other ends of many of those wires are connected to places in the harness that have power to them (some at times, some 24/7) so if the lopped-off wires ever touch each other or ground you'll have some mysteries to solve. Several of them aren't fuse-protected, either, so if they should short they could damage the adjacent wires in the harness as they go up in smoke :(

You may want to go to every "orange dot" on the wiring diagram and disconnect each wire there to ensure bad things can't happen.

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