Help ID 356a Mystery wiring relay

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Robin Robbins
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Help ID 356a Mystery wiring relay

#1 Post by Robin Robbins » Sat Jan 06, 2018 3:42 pm

Well, a mystery to me anyway. Im in the process of hooking up my wiring harness etc on my 356a (56) coupe and I found this relay in the box of “should have been labeled better” stuff. I appears to be a lighting relay (I discern this from one side being stamped “light” and the other “switch”!) but I havent been able to see where it goes.
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Robert Reed
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Re: Help ID 356a Mystery wiring relay

#2 Post by Robert Reed » Sat Jan 06, 2018 10:01 pm

Robin,
That is an old-school headlight relay, likely 6v. It could be used on a 356 to relieve power going through your headlight switch. I have seen one mounted behind the spare tire, where it is fed straight off the battery to power the lights.
Actually pretty effective in that regard, too. Check it to see if it works.
Bob

Robin Robbins
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Posts: 37
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Re: Help ID 356a Mystery wiring relay

#3 Post by Robin Robbins » Sun Jan 07, 2018 1:32 am

Thanks for the reply. Anywhere I could see a diagram showing how that is wired into the circuit?/Robin

Robert Reed
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Posts: 89
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Location: Lascassas, TN

Re: Help ID 356a Mystery wiring relay

#4 Post by Robert Reed » Sun Jan 07, 2018 12:29 pm

Robin;
Try looking on EBay for dual headlight relay. I tried posting a pic of each side of the instructions sheet for you, but alas they were too large. I could email them to you if needed.
Bob

Robert Reed
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Re: Help ID 356a Mystery wiring relay

#5 Post by Robert Reed » Sun Jan 07, 2018 12:40 pm

Robin;
Will post one at a time; all from one side of instruction sheet.
Bob
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Robert Reed
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Re: Help ID 356a Mystery wiring relay

#6 Post by Robert Reed » Sun Jan 07, 2018 12:44 pm

Robin, one more for you. The third wouldn’t apply for you.
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Robert Reed
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Re: Help ID 356a Mystery wiring relay

#7 Post by Robert Reed » Sun Jan 07, 2018 12:55 pm

Robin stay with me...
I’m trying
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Greg Bryan
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Re: Help ID 356a Mystery wiring relay

#8 Post by Greg Bryan » Sun Jan 07, 2018 1:16 pm

Robert - impressive that you recognized, then found the instructions for this light relay. I've never seen one before. Looks like it would work fine.
Robin - here's the schema for a standard T2 headlight system (very similar to T1) to help you with the wiring.
Lights 356A T2.pdf
(264.72 KiB) Downloaded 36 times
The more typical wiring of light relay kits that are available is below.
Lights 356A T2 with Switch Saver Relays.pdf
(271.44 KiB) Downloaded 30 times
I imagine the relay you have is similarly constructed but all in one package.
Greg Bryan
356Talk Moderator

Robert Reed
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Re: Help ID 356a Mystery wiring relay

#9 Post by Robert Reed » Sun Jan 07, 2018 2:36 pm

Greg, thank you for the compliment, but with all due respect, I would like to compliment you for your efforts on your columns in the Registry magazine. I’m currently doing a rewiring job on my T6 B and have found them quite invaluable in my efforts.
Greg, I have a couple of questions regarding that effort and wondered if you might have an answer. I was reading 356 Electrics and it mentions a ring that mounts on the flasher relay. My car didn’t have one on it and thought maybe you had a picture of what one looks like or if they are available.
The other question is about the spade clip on the speedometer bracket; what hooks up to that?
Robin, sorry for hijacking your thread.
Bob

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Greg Bryan
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Re: Help ID 356a Mystery wiring relay

#10 Post by Greg Bryan » Sun Jan 07, 2018 3:25 pm

Robert - well, thank you back for the compliment.
The plastic ring referred to by Mr. Leone is a mount - the two pieces, the flasher socket (which is a headlight connector) and the mount are screwed to the bulkhead under the dash if memory serves. I think YnZ has reproduced the parts.
The spade clip on the speedo bracket is for an additional ground wire for the instrument lights if you need it. Usually, the bracket will ground to the dash where the ends of the bracket fingers rest, but this is a more reliable ground. The other two instruments have a dedicated ground wire.
Robert, do you know who manufactured that headlight relay? I guess it stands to reason that back in the day when virtually all cars were running 6 volt that there would be a high demand for this unit.
Greg Bryan
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Robert Reed
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Re: Help ID 356a Mystery wiring relay

#11 Post by Robert Reed » Sun Jan 07, 2018 4:07 pm

Greg and Robin, the brand name of the relay is Preferred, and the part number is LR66.
Bob
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Robin Robbins
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Re: Help ID 356a Mystery wiring relay

#12 Post by Robin Robbins » Sun Jan 07, 2018 6:46 pm

Well, thanks to all. I think even I will be able to wire it into the circuit now. Speaking from a place of ingnorance, what is the purpose of this relay? It isn’t standard issue so what is it supposed to do?

/Robin

Robin Robbins
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Posts: 37
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Re: Help ID 356a Mystery wiring relay

#13 Post by Robin Robbins » Sun Jan 07, 2018 7:03 pm

Ignorance, not ingnorance. Anyway, a little research indicates the idea was to improve the light output on 6 volt systems. Nice idea but Im not sure I need to put that in the circuit. I’ll see when I get to the point of actually hooking up the battery. /Robin

Robert Reed
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Re: Help ID 356a Mystery wiring relay

#14 Post by Robert Reed » Sun Jan 07, 2018 9:22 pm

Hey Robin,
The idea behind the relay is twofold, in that it saves your headlight switch from having to carry load from the fuse block through the switch and then to the headlights. My switch is 56 years old, so it’s likely getting a little weak inside.

The other bonus is that with the relay mounted next to the battery allows for a very short run with little or no voltage loss to those headlights.
Not trying to talk you into anything, just explaining the benefits associated with the relay.
Bob

Robin Robbins
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Posts: 37
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Re: Help ID 356a Mystery wiring relay

#15 Post by Robin Robbins » Sun Jan 07, 2018 9:38 pm

And I appreciate the input. If not for the help from folks on the forum my progress on this incredibly long term project would be even slower than it has been. /Robin

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