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MYSTERY Knob! Who Can Name It?

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Old 09-30-2015, 05:33 PM
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GraphicFeedback
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Default MYSTERY ****! Who Can Name It?

We're looking at a '72 (Edit: Convertible) with all your power options and A/C. I have little idea what this **** and these wires could be for. The radio doesn't work, and I have a feeling these may all be the reason why? Only other things in the area that appear inoperable are the center console gauges. Likewise, I found a mystery red wire with electrical tape that was threaded through and dangling by the shifter ****, but I think that's unrelated.


Here's the **** in question. He refuses to talk! Give 'em hell, boys!




Flip side of the panel (Driver's side center console). Two obvious wire connection points...




Local area busted wire. Not sure if related since the short end wouldn't reach the ****, and there is a 3rd wire tear on the opposite side.




Passenger side broken wire for reference. Long enough to reach driver side of console.



Any ideas or guesses would be greatly appreciated. I'm hoping it's something I can fix up myself with my little car/wiring knowledge.

Last edited by GraphicFeedback; 09-30-2015 at 05:59 PM.
Old 09-30-2015, 05:43 PM
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Nowhere Man
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I think bubba was there
Old 09-30-2015, 05:48 PM
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marshal135
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That was the factory placement for a rear defroster switch.
Have to see if defroster unit is still there.
Check under rear window behind drivers side seat.
Marshal
Old 09-30-2015, 05:55 PM
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Giant_Robot
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Default MYSTERY ****! Who Can Name It?

looks like a potentiometer... for volume control, possibly for a line to a powered sub woofer?... who knows. Dig up the previous owner and ask them with a Ouija board.
Old 09-30-2015, 05:57 PM
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GraphicFeedback
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Originally Posted by marshal135
That was the factory placement for a rear defroster switch.
Have to see if defroster unit is still there.
Check under rear window behind drivers side seat.
Marshal
I haven't considered that. This a convertible though; Would that still apply since it's a soft top?
Old 09-30-2015, 05:59 PM
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Peterbuilt
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Hi and welcome!
Not 100% sure about the wire in the third picture but if it's brown it might attach to the parking brake switch, does the dash 'brake' light go on when you pull up on the parking brake?

For the center gauges is the fuse good?

Here's a schematic, it's good except the direction of rotation for the distributor should be clockwise.
http://www.vetteprojects.com/bmv/mis...tte%201972.pdf

Regards, Pete.
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Old 09-30-2015, 06:02 PM
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GraphicFeedback
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Originally Posted by Nowhere Man
I think bubba was there
We'll find him eventually...


Seriously though, what? haha
Old 09-30-2015, 06:05 PM
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Originally Posted by Peterbuilt
Hi and welcome!
Not 100% sure about the wire in the third picture but if it's brown it might attach to the parking brake switch, does the dash 'brake' light go on when you pull up on the parking brake?

For the center gauges is the fuse good?

Here's a schematic, it's good except the direction of rotation for the distributor should be clockwise.
http://www.vetteprojects.com/bmv/mis...tte%201972.pdf

Regards, Pete.
Thank you, Pete, I'll take a look. The parking break doesn't do anything at the moment, including brake!

I'm not use to these tube-shaped fuses, so I'm unclear on how to check their quality. I did just get a whole replacement set in the mail... I'm thinking about just swapping them all out. hahaha
Old 09-30-2015, 06:07 PM
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GraphicFeedback
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Originally Posted by Giant_Robot
looks like a potentiometer... for volume control, possibly for a line to a powered sub woofer?... who knows. Dig up the previous owner and ask them with a Ouija board.
So when you say dig up...
But I think you might be right. Or at least that's what Google Images thinks.
Old 09-30-2015, 06:25 PM
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It looks like in the 3rd and 4th picture the wire has clear insulation those look like wires for the rear speaker. Hope you can figure things out, I have a wiring problem I have not been to find the problem yet, guess I will keep looking. Good luck.
Larry
Old 09-30-2015, 06:38 PM
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Originally Posted by Peterbuilt
Hi and welcome!
Not 100% sure about the wire in the third picture but if it's brown it might attach to the parking brake switch, does the dash 'brake' light go on when you pull up on the parking brake?

For the center gauges is the fuse good?

Here's a schematic, it's good except the direction of rotation for the distributor should be clockwise.
http://www.vetteprojects.com/bmv/mis...tte%201972.pdf

Regards, Pete.
Just replaced the gauge fuse! It was all red and nasty inside! After replacing it (accidentally shattering the old one trying to get it out), I saw instant feedback in my battery and oil gauges. Parking brake light works too. I'll have to take her for a spin and hope the gas and water temp work as well. Thank you! I know gauges are kind of a simple thing to check, but the focused answer geared me in the right direction.

Last edited by GraphicFeedback; 09-30-2015 at 06:42 PM.
Old 09-30-2015, 08:32 PM
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croaker
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That's a odd switch for Bubba to use I would think it would be a plastic toggle.
Old 09-30-2015, 10:22 PM
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0Willcox Corvette
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I kind of think it was a visit from bubba and used for something different.

If you look at the AIM pages you'll see the rear defroster switch had screws that held it in place. (none shown in the op's picture)... even if it was replaced there would still be the extra holes.

Old 09-30-2015, 10:27 PM
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Jalopy Bob
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The wire is speaker wire, and the **** was probably Bubba's fader.
Old 09-30-2015, 10:56 PM
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As others have identified the 'mystery ****' is a potentiometer and was generally used as a fader to balance rear speakers.

Here's a diagram of how it should be wired. The more resistance dialed in made for less volume out the speaker.
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Old 09-30-2015, 11:26 PM
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Thank you all! Looks like you're onto something. And I think I'm starting to grasp who Bubba is. I would love to get that radio working; I suppose I just have to start tracing which wires need to be connected where...?


...To be completely honest I don't even know where the dang speakers are on this car. haha
Old 10-01-2015, 06:18 AM
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7T1vette
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The add-on rear speakers have likely been removed...which is why the speaker wires have been cut up front. Nice to have those wires in-place, though; you may want to reuse them. That 'fader' control didn't have enough current capacity to do its job...so it fried.

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Old 10-01-2015, 07:45 AM
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Easy Mike
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Originally Posted by Nowhere Man
I think bubba was there
I agree. Looks like speaker wire if the wires in the pic were ever conected to it. Some type of homegrown sound system.

Last edited by Easy Mike; 10-01-2015 at 07:47 AM.
Old 10-01-2015, 09:22 AM
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Alan 71
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Hi GF,
I too am thinking 'fader switch'.
And yes, convertibles could have the rear defroster option too as the drawing Willcox posted illustrates.
Regards,
Alan
Old 10-01-2015, 10:09 AM
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It looks like an ATR device. I wouldn't recommend connecting it.


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