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esde Samba Member
Joined: October 20, 2007 Posts: 5927 Location: central rust belt
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Posted: Wed Jul 18, 2012 10:11 pm Post subject: 62 turn signal wiring diagram issue |
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I have finally gotten around to installing the speedometer into my 62, and connecting the lights. Charge light stays on, but a reading at the battery tells me that the generator is putting out above idle. Anyway, that's not the problem. I connected the turn signal dash indicator wire to terminal 49a, as it is supposed to be, at which point the turn signals stopped working. Disconnected, the lights all work perfectly. I started staring at the diagram, and realized, that both terminals are shown connected to fuse #1, and that the bulb is not grounded. Both warning lights and the turn signal light share a positive connection to fuse #1. It is hot whenever the key is on. The oil pressure warning light and charging warning light both supply a ground to the bulbs to make them light. The turn signal indicator will light up if I ground the bulb connection, but this diagram,
http://www.thesamba.com/vw/archives/info/wiring/bug_62-65withinset.jpg
says connect it to 49a, and that supplies positive. And then nothing works. Is there a problem with the diagram posted? Is there some part of automotive electrical theory I'm missing? It will work if I separate it from the other 2 lights entirely, and give it a ground, but I'm wondering if there's another problem. Thanks, Seth |
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glutamodo The Android
Joined: July 13, 2004 Posts: 26300 Location: Douglas, WY
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Posted: Thu Jul 19, 2012 8:02 am Post subject: |
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Actually, 49a supplies a ground, well almost a ground.
As you said, the all three bulbs at the bottom of the speedometer are hot when the key is on, and then light up via grounds on the various circuits (oil pressure switch, voltage regulator) and for the turn signals, well originally they used a "K" or "kBL" terminal on the turn signal relay that had specific contacts that provided the ground when the turn signal was in operation. Then they got rid of that in mid 1963, as the note at the bottom here shows.
S is the same terminal as 49a on modern relays. As it says above, the original relays at the time were grounded as well - they just don't show that on the wiring diagram. replacement relays have 31 as a dedicated terminal.
So the wiring diagram is correct - (I drew up that diagram myself) and it's how I've had my own 62 going for many years, first with a late 60s Bus metal-can style 3-terminal flasher relay, then after that one started getting flakey, with a later 70s vintage VW 3-terimal flasher. In mid 1968, VW went back to a grounded 4-terminal relay, but again must have decided it was needlessly overcomplicated because in 1971 they went back to the 3 terminal flasher, and they used that setup on almost all models from through the 3rd generation of Golf/Jettas (early 1999)!!! If you look at any wiring digram from 1972 on, you'll see this is how it's wired.
So to answer your question - how does the turn signal light up? Well it's like this: When you engage the turn signal switch, the relay powers up, you then have 12V on either side of the dash arrow bulb. It won't light up with equal potential on each side of it. But... then the relay clicks off, and suddenly you have a very low resistance of turn signal bulbs themselves on the circuit in operation, and it is through that almost-ground that makes the dash bulb light up. The dash arrow bulb will thus light up opposite of the outside lights - in/out/in/out..
Your problem sounds like it might be a bad turn switch - did you try bypassing it entirely?
-Andy. |
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esde Samba Member
Joined: October 20, 2007 Posts: 5927 Location: central rust belt
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Posted: Thu Jul 19, 2012 10:51 am Post subject: |
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Andy, thank you for the detailed reply. It makes a little more sense now, but it just seemed to make MORE sense if the turn signal indicator bulb had its own ground, and did not share the fused hot with the oil and electric warning lamps. As for it getting a ground through the lights themselves as the relay flipped back and forth from on to off, I get it now, but it seems overly complicated. I may just get a plastic bulb holder with a separate ground, if a bit more testing doesn't reveal the problem. It may be difficult to diagnose, as I am running a trailer converter for the snowflakes in the rear, and it is the converter for running LED lights, so it may be interfering with the ground, and be the cause of this. Like I said, with out the indicator, everything works fine, if not a bit faster flashing. The TS relay is one I pilfered from an 80's Rabbit, 31 to ground, 49 to fuse, 49a to turn signal switch and indicator light. I'll bypass the switch, and the converter, and see if either makes a difference. Thanks again, SD |
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glutamodo The Android
Joined: July 13, 2004 Posts: 26300 Location: Douglas, WY
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Posted: Thu Jul 19, 2012 2:24 pm Post subject: |
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Ah, yeah, it might be that trailer converter.
With an isolated bulbholder, you do get more options. VW's way of doing it may sound complicated but it's actually pretty simple - it allows for a simpler turn signal relay - those extra contacts for Kbl on the 4-terminal Euro spec flashers can go bad while the main flasher contacts stay functional - there's been more than one person that has had that happen, and I told them to move the wire over to 49a with a piggyback, and that got their dash light working again. |
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