running wires

[JaxWaxMan]

I've posted about my alternator a few months ago and got a new alternator and the idiot light won't go on. I'm thinking I need to replace the wire completely. Any suggestions/hints to do that? I need to replace the oil one too...

thanks!
JaxWaxMan

[Cusser]

I personally have routed wires from front to back in both my 1970 and in my 1971 VW convertible. This was for gauges, and as a new wire for the #15 wire back to the coil (for which I now have an in-line fuse).

I routed the wires out from the trunk through an existing grommet, under the driver side running board then up and under into the engine compartment. I ran the wires using existing nooks and crannies, wherever there was a convenient place to let existing bolts, gaps to hang the wires. Of course you can use good-quality cable ties to help keep things in place.

By the way, I first did this in the 1970s, so my two VWs have been running fine like this for 4 decades...
OK, some photos, under front driver fender

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1970 VW (owned since 1972) and 1971 VW Convertible (owned since 1976), second owner of each. The '71 now has the 1835 engine, swapped from the '70. Second owner of each. 1988 Mazda B2200 truck, 1998 Frontier, 2014 Yukon, 2004 Frontier King Cab. All manual transmission except for the Yukon. http://www.thesamba.com/vw/forum/album_page.php?pic_id=335294 http://www.thesamba.com/vw/forum/album_page.php?pic_id=335297

[JaxWaxMan]

Wow, that's great! So would I run the oil and generator wires directly from their respective plug ins on the engine straight to the bulbs in the speedo? I'm a rookie as you can tell, and the electrical part has been vexing me for a couple of months now....

thanks!

[bomberbob]

Cussers method would work. You might consider covering it with split loom to provide a little protection from the elements. Thats what John Deere does with their ag equipment. If split loom isn't used, placing a few zip ties every 4 or 5 inches will hold the wires together into a bundle. I have to run wires myself, my cylinder temp gauge has a problem with the wire, so I am running a new one. I am running mine underneath the car, through a metal tube. I don't want mine in the fenderwell, although its worked for cusser. My personal preference.
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1968 Beetle (storage)
1990 Jetta GLI megasquirted, burning E85 (currently in heavy maintenance)
2004 Jetta turbo GLI
Marion, Iowa

[scarabee]

Did you test the wire by removing it from the Df terminal on the generator and grounding it? The light should come on. If it does, the wire is fine. If it doesn't, the problem is with the generator.

[ashman40]

@OP, which alternator do you have? 2-wire (AL-82) or 4-wire (AL-78 )?

First make sure the GEN lamp in the speedometer is working. Easiest way to do this is to turn the key to the ON/RUN position (engine not running), then use a jumper wire to ground the wire coming off the GEN lamp bulb holder (blue wire). This should turn the GEN lamp ON. If this doesn't work, swap the bulb (or bulb+bulb holder) with another and retest. Once your know the GEN lamp works move on to the next step.

If you disconnect the D+ wire from the alternator and ground the D+ wire to the body of the alternator with the ignition switch in the ON/RUN position (engine not running) the GEN lamp should turn ON.

The wire coming off the GEN lamp bulb holder (blue) runs to the D+ circuit at the alternator (2-wire) or the D+ wire at the VR if you have an externally regulated alternator (4-wire). Grounding the D+ wire grounds the GEN lamp which turns it ON.


FYI, even though the above suggestion to run a wire to the engine area... you could opt to follow the stock wiring harness. The stock wires ran from the front trunk area down the left A-pillar and ran along the floor next to the left heater channel. The harness then ran up inside the left rear quarter panel and through the C-pillar into the engine compartment. VW injected foam into the C-pillar area to seal out the engine compartment. Getting a wire through the foam is a challenge but not too difficult. I was able to dig thru with a straightened coat hanger. Once thru, use the coat hanger wire to pull the new wires thru the C-pillar and into the engine compartment.
If you are running new D+ and OIL lamp wires I recommend you add a couple extra wires for future expansions (eg. tachometer, oil pressure, oil temp).
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AshMan40
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'67 Beetle #1 {project car that never made it to the road }
'75 Beetle 1200LS (RHD Japan model) {junked due to frame rot}
'67 Beetle #2 {2019 project car - Wish me luck!}

[JaxWaxMan]

To make sure I’m understanding what you’re saying, all I have to do is run a new wire from the gen light or oil bulb through the body onto their respective spots? There’s no junction in between? Thanks for all your replies guys, this is very helpful!

Jax Wax Man

[ashman40]

[JaxWaxMan]

Mine is definitely an internal regulator alternator. One red wire and one slip on blue wire for the generator light. So does that mean I just run a wire from the alternator to the generator Boban the speedo? Same with the oil light? That would be easy…

[Michael Ambrozik]

If you are going to run a new wire pull the old one through the harness with a strong string (nylon) and pull the new wire with the string. When pulling wires like this be careful you take your time and pull 2-3 at a time, and use lots of lube, K-Y jelly works great.

[JaxWaxMan]

Well I found the breaks in the wires, butt connected them back together and all is running well! Thanks for everyone's help.

JaxWaxMan