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nlorntson Crazy VW Lady
Joined: March 13, 2004 Posts: 3783 Location: Twin Cities, MN
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Posted: Sat May 02, 2015 4:15 pm Post subject: Electrical gremlin - Chasing a wiring problem **SOLVED** |
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I'm chasing down an electrical problem in the headlight switch. The pod was rebuilt by Jim Bremer (who did a beautiful job) some 10 years ago.
I'm using a 5A fuse to go through testing the different circuits. I'm popping a fuse on the headlight switch any time it is turned either way.
Here are the scenarios:
Battery in line behind a 5A fuse - KEY OFF
- Turn switch left or right and the fuse blows
- Switch in center position, I have power to terminal 30 and no power to 56, 57 or 58
Now with the battery un plugged and just checking continuity on the switch
- Switch in center position, No continuity between terminal 30 and 56, 57, 58
- Turn the switch to either side, I now have continuity between terminal 30 and all others (56, 57, 5.
It seems to me like turning it one way I should not have continuity to the same terminals as turning it the other way.
Does it sound like I have a bad switch (or incorrectly assembled) or is something else going on?
Before I pull the whole pod out is there anything else I can check?
Last edited by nlorntson on Wed May 06, 2015 12:51 pm; edited 1 time in total |
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johnshenry Samba Member
Joined: September 21, 2001 Posts: 9363 Location: Northwood, NH USA
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Posted: Sun May 03, 2015 7:27 am Post subject: |
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A couple immediate thoughts, and I will look at wiring diagrams and a pod later...
Are the headlights and bulbs wired in? Head light fuses in place? I'd start by pulling the head light fuses and see if you get the same result.
Another common short area is the dimmer switch. Make sure that the exposed soldered leads are not shorting against the switch case. Clip them shorter if needed. You might also disconnect the dimmer switch completely and see if you get the same result.
Lastly, head light bulbs are 35 watt I think, that is a shade under 6 amps each. If you are using a 5amp fuse to test at the switch location, it will blow of the bulbs are switched in. Should not in the running light position though, that load should just be 4x5w + 1x 3W, 23watts, about 4amps. _________________ John Henry
'57 Deluxe
'56 Single Cab |
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nlorntson Crazy VW Lady
Joined: March 13, 2004 Posts: 3783 Location: Twin Cities, MN
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Posted: Sun May 03, 2015 8:21 am Post subject: |
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johnshenry wrote: |
Are the headlights and bulbs wired in? Head light fuses in place?
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Yes everything is wired in. Good suggestions. I'll try each and report back.
Thanks John! |
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nlorntson Crazy VW Lady
Joined: March 13, 2004 Posts: 3783 Location: Twin Cities, MN
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Posted: Sun May 03, 2015 8:34 pm Post subject: |
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I dug into this most of the day today. I pulled all the front fuses and left the rears but the 5A kept popping when the parking lights were switched on.
Next I tried with all the rear fuses pulled and the fuse did not blow.
Next I added in the brake light fuse in the back - still OK.
Added in the brake fuse in the front. - OK
Added in the parking light fuse in the front - OK
Added in the left rear taillight fuse (the center one) - OK
Finally added in the right rear taillight fuse - POP!
It's at this point I'm really scratching my head. What about the right rear taillight is bad? They cannot be any simpler, a single wire to the bulb holder
I pull out the bulb and it still pops. WTH??? Then I realized that these taillight wires are aluminum wrapped. What's the chance....
Yep, I tested the wrapping and sure enough I had current flowing through the wrapping. I looked closer and realized that at the fuse box the wrapping was indeed in contact with the terminal.
So, I guess what was happening is the wrapping was touching terminal at the fuse box and picking up current. Somewhere through the rear apron and on to the taillight it must have found some bare metal to ground to.
I peeled back the wrapping on both ends of both wrapped wires and I can now turn on all the parking lights without the fuse blowing.
YAY!
I'm on to the higher voltage circuits tomorrow. |
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