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I've seached for info on wiring relays into the headlight circuits and found lots of people who have done it, but no schematics. I know M.A.D. sells a kit for $24.00 but I already have numerous 30amp Bosch relays and sockets. Does anyone have a good schematic of how to wire them in using the horn relay buss or directly from the battery - explaining where each wire comes from and which post it goes to on the relays?

I found this example on the web, but no relay lug identification. With instructions like:
1. Turn on the lights and use a test light to find out which color wire goes to which bulb terminal. ---THEN---
2. Cut the wires going to the headlight bulbs and reroute them to each relay's terminal 85.

One headlamp has 2 wires, the other has 3. Cut WHICH wires and hook them to terminal 85? Is there a separate relay for each headlamp (4) or does one relay work for 2 low beam and one for 2 high beam? There is also a nice schematic but the relays lugs aren't marked.

I'd like to use a setup on both my 67's but can't find "complete" instructions. Anyone help with pictures? :D
 

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In the example they are using two relays, one for high beam and one for low beam

I don't know the colors of the wires on the 67 headlights but you could easly find out which is which with a test light since each one will have one hot feed wire on dim and one hot feed wire on bright


I'm not familiar with the relay terminal numbering but I assume #30 is common, #87 is normally open, #87a is normally closed and #85 & #86 is the operating coil

I wonder why they use a SPDT relay when the N.C. contact is not used, seems like they would just use a SPST relay :confused:

I didn't see the connection from the dimmer switch in the diagram so I drew it in



 

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Discussion Starter #3
Thanks for the assistance on the diagram. I assume the diagram is only to wire the outer lamps in a quad headlamp setup since these have both low and high beam circuits. Using a tester is easy enough to find out which wire of the three is which and should then be a simple matter of splicing in the relays I would assume. I'll corner you at CB for more :D

See everyone there.
 

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It has been a while since I read about this (still on my file of things I'll get around to), but seems like the lights are wired in series and by cutting in ahead of the drivers side light you caught all 4 low beams with one relay and both high beams with the other.

Just looked at the Service manual schematic (posted on your site), it shows the 16 ga light green wire in the lighting harness goes to all 4 low beams, and the 16 ga turqoise wire powers the brights. You should be able to tap in by the horn relay to catch them all
 

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Discussion Starter #5
Originally posted by rthlc:
Just looked at the Service manual schematic (posted on your site), it shows the 16 ga light green wire in the lighting harness goes to all 4 low beams, and the 16 ga turqoise wire powers the brights. You should be able to tap in by the horn relay to catch them all
Boy, directing a guy back to his own site for information...how cruel can you be? :D I guess I forget stuff I have spread around 4 web sites.
Appreciate the guidance.
 

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It's the other way around. You normally have 2 low beams and 4 high beams in the four lamp system.

And the circuits are wired in parallel, not series.

I run four low beams and four high beams on my car, switched by a pair of the same little $2 relays that I use for the wipers and the electric fan. Those things are great for carrying current.
 

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Just playin around here but you would need to cut the 16 LG and 16 T wires and connect the ends coming from the dimmer switch to; 16 LG to #85 on high beam relay and 16 T to #85 on the low beam relay and the ends coming from the bulbs to; 16 LG to #87 on the high beam relay and 16 T to #87 on the low beam relay



I assume 16 LG means 16 gauge - Light Green & 16 T means 16 gauge - Tan

if that's the case, then 20 B must mean the grounds are 20 gauge Blue

what do you think cj ?
 

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It's the other way around. You normally have 2 low beams and 4 high beams in the four lamp system.
Chad - DOH! That's what I get for pointing Dale back to his site!

Dale - Your site has been so valuable for me, in fact it was a search of the web for 67 schematics which led to to your site and from there I first found TC! THANKS A MILLION!
 

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I think you're absolutely right, Dean. I'm pretty sure you got the colors on the money too.

Since there's not an original wire in my car, color codes don't count for me.

I ran an 8-gauge wire from the battery's positive post to a junction block. I picked up from there with 12 gauge wires into T-30 on the relays. Then from T-87 to the plugs on the lights. I energized T-85 with the wires from the switches. I grounded everything, including the lamps, to the radiator support.

Just use your LG and T wires to energize the relays. Run new wiring for everything else.

Everything's nice and bright, and there's virtually no load on my headlight switch or high-beam switch.

I recommend upgrading wire size from the relay to the lamps if you're running modern headlamps.
 

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Dale. As you will probably know the headlight switch acts as a circuit breaker as well. Using relays this function is voided.

I would strongly advise you to fuse the lead from the junction/battery to "replace" this circuit breaker function.

Rob
 

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Originally posted by rusty66:
Dale. As you will probably know the headlight switch acts as a circuit breaker as well. Using relays this function is voided.

I would strongly advise you to fuse the lead from the junction/battery to "replace" this circuit breaker function.

Rob
Very good point, I never even thought of that

The existing circuit breaker would only be protecting the wires going to the relay(s) coils(s) and dimmer switch
 

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Check the schematic on David Sterns page >tech>relays its got the fuses in line
 

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Originally posted by rusty66:
I would strongly advise you to fuse the lead from the junction/battery to "replace" this circuit breaker function.
Good call! I completely forgot to mention the 25-amp inline fuses in my circuit. One for the highs and another for the lows.
 

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Discussion Starter #16
I was thinking of taking the power off my Painless Cirkit kit which has 3 unused "always" hot connections. It's wired to the battery post with a circuit breaker in that line plus each ign hot and always hot line is fused separately. That should work instead of a direct line to the battery or off the horn relay buss. Think?
 

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I think the Painless kits are only rated for 30A continuous which would be on the light side for headlights. Make sure it has 10 gauge feeding the fuses and something like 16 coming off each fuse and you should be OK. I don't know where you've got this circuit block installed but if it isn't on the rad support then you're negating some of the reason for running relays. The idea is to put the relays and wiring in the most direct line from the battery to the lights.

Finally, it's probably a good idea to upgrade the wires and sockets to the lights as well because the wires are on the light side to begin with and the terminals in the sockets are probably corroded and loosing their ability to hold the light terminals correctly. Alternatively, you could use a set of relays for the lights on each side of the car and split the wiring harness. This also provides a back-up in case one of the relays fails (high or low lights fail on one side only).

Peter
 

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I'm going to be wiring up my whole car this weekend with the painless 18 ckt. kit. I also ordered some extra relays and wire so I can wire up the headlights via relay. I plan on using 1 relay for the low beams, and 1 relay for the high beams. I am going to wire it up so all 4 lights run at the same time, with both the highs and the lows. I'll let you guys know how it all works out.
 
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