[dbm063]

I've got two electrical problems with the left rear of my daughters 2001 Beetle.

First, she was told that the left rear side marker was out. I confirmed this, replaced the lamp and nothing. The contacts were rusty though so I pulled the connector, checked the resistance and found one of the leads was bad. I went out, got a replacement and still nothing. Finally, I checked the voltage and got .019V - the right side marker (which works fine) is showing 10.9V. So clearly a problem there.

However, along comes the second issue. I pulled the left tail light housing out to get a better look at the harness and get my bearings. After putting it back together, I found the left rear running light (the filament always lit when the lights are on) is no longer working. It was fine before i pulled the housing and is now only getting .24V.

The left brake light and turn signals work fine. The license plate lights and everything on the right rear are fine. As I'm writing this, it occurred to me that I didn't check the 3rd brake light so I'll have to post an update regarding that.

So any ideas on what's going on here? Given both are providing a bit of voltage, I'm thinking a grounding issue but just don't know the rear wiring on this car very well. Thanks for your time and any input you can provide.

Dan.

 

[billymade]

The sockets getting damage from heat; is the typical problem we see, replacement with a genuine vw part is the fix for that (aftermarket versions; from Dorman have inferior quality issues, bad reviews). The heat, makes the bulb loose and makes the contact//connection to the bulb intermittent.

Beyond the bulbs, socket: the plug, terminal ends maybe a issue; you could test the voltage, using a sewing "t" pin and back probe the terminals, to check for correct voltage. A bad plug/terminal ends, can be replaced with new parts from your vw dealer and splice inline with a butt connector, (be sure to use the heat shrink, adhesive lined, weather sealed type). You can also, get the part number off the plug and search online, for a preassembled aftermarket pigtail assembly (sold on amazon/ebay).

If all that is ok, looking at the wiring diagrams, grounds and related parts, would be next thing to check. So, far, we typically see the plug or sockets causing intermittent, connectivity problems with the bulbs.

 

[dbm063]

@billymade, thanks for the input.

I checked the harness leads at the connector and am still getting .24V so the issue is somewhere in the harness - either inside the trunk or after after it passes through the sheet metal below the left brake light housing. I was hoping to not have to start seriously messing with the harness but am not seeing I have much choice at this point.

Does anyone know if there are any other components in the rear harness (relays, etc) or is it pretty much straight forward wire harness? Also, any ideas whether the harness is in sections or is it just one harness covering the whole rear?

 

[red99]

The left side marker lights and tail light are the only things on fuse 23 so you should definitely check the voltage there first. Could be nothing more than bad contacts in the fuse and it will help isolate the problem further.

 

[red99]

Fuse 23 comes after the ignition switch in the circuit so if you see the problem there, suspect the ignition switch.

 

[red99]

Sorry, I meant headlight switch, not ignition.

 

[dbm063]

@red99, Much appreciated. That definitely gives me some things to check before burrowing into the harness.

 

[dbm063]

Problem solved so to close this one out..

The problem turned out that fuse 23 was mostly bad. It was passing a tiny bit of voltage before pulling it. After taking it out, the fuse visually looked fine (meaning the little S shape seemed intact) but I noticed one of the legs on the fuse wiggled a bit. I checked continuity with the multimeter and got nothing (ohms off-scale high). I put it back in and re-tested the voltage at the rear and nothing this time so I'm thinking pulling it killed it completely. In goes a new fuse and all the lights are back.

Thanks for helping me out!

Dan.

 

[billymade]

Good work; glad you got it fixed.


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