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Was reading about using a relay for headlights..the person used two relays, one for low beams, and one for high beams, won.t a dpdt relay work?..

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The idea is to get all the heavy lamp current out of the headlight and dimmer switch. Less stress on switches and less voltage drop to lamps.

Using a DPDT relay, fused but contacts fed directly from power source as relays typically are wired would mean that the beam on the normally closed contact would be on even when lights are supposed to be off.

The typical setup has the relay commons wired to power with the N.O. contacts to the beams. That way neither beam is powered unless commanded. The headlight switch then only has to power a few milliamps to the coils thru the dimmer switch. That switch selects the appropriate relay to carry the 10-15 amp current. When headlight switch is off, neither relay is on so no lights.

Thanks, Howard,, think I will add that to my to do list.

Mine too.

For reference, 2 relays (preferred way), and 1 relay (load on dimmer switch).

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Many ways and locations to do the relays. Some have been under the top radiator splasher, others nearer the dimmer switch. When I did mine for the 56 it was as a module so it can be easily removed and reverted to original. It is fairly well out of sight unless you look for it.

Made a cradle so the relays could slide in and be secure. They are in a double socket which I custom wired for the purpose. A few inches of extra pigtail is provided to be able to remove relays from cradle. Mounted all using existing holes in radiator cradle just behind the horn relay. Removed the existing wires to headlight from L junction block and relocated to terminal strip on module. A separate heavy cable from the terminal strip runs to right side along front of radiator cradle where horn wire is placed. Another terminal strip is mounted on a plate in the same space in R side of cradle. Rt headlight wires relocated there. Original strip remains in place to hold original wires but is essentially unused.

The power for relays comes from a short cable between relays and the original headlight connection from dimmer switch. The schematic is as Kevin shows except I used a 20amp self resetting circuit breaker -- just as original headlights had -- instead of the fuse. Connected to bat post on solenoid along with all the other accessory feeds. Adapted a modern ATC blade type fuse holder for that blade style breaker. Located by emergency brake ratchet and protected with heat shrink to ensure breaker stays protected and securely in holder. All remaining lights are as original off headlight switch and protected by the original breaker.

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Havn't followed this real close. But i would not wire up any relay to the design that if the relay fails then lose BOTH head lites. If the double relay circumvents that problem then the double would be best. Persanally i find the relay for headlites to be extraneous. But would it not be more fail safe to use a starter relay(s) rather than to use a 'litle black box' modular type relay???

Same concept with fuses. a seperate fuse for EACH headlite.

Keith, relays are cheap, reliable and readily available. Packard Headlight switches are not.

I've never had one of those Bosch style "cube" relays every fail on me. Only time they generally would is if someone was running them over their rated current handeling value.

No different than original design. On that only a single CB for all lights and if you lose any portion of the dimmer switch, you also lose both lights. And, as I said this one is modular so 5 minutes or less with a screwdriver on either (or both if you want) sides and light is back -- assuming the dimmer or headlight switch wasn't the failed item. The relays I used are good for 40 amps which should be quite sufficient.

Yes, i run the little cube type on Fog lites. Never any problems. But still would prefer seperate circuits for each headlite.

Also when buying fuse holders for soemting as important as the headlites be sure to get NAME BRAND (such a "LittleFuse") fuse holders. Name should be moulded into fuse holder. I've had at least 2 maybe 4 no-name brand fuse holders fry before the fuse blew.