The Stovebolt Site Forums The Shop Area The Electrical Bay Headlight Relay Kits Information

Headlight relays started appearing during the mid to late 1950's, beginning on cars, then later on trucks. A headlight relay will give you brighter headlights and greatly extend the life of your original headlight switch. A typical 6 volt headlight switch is expected to carry 20 plus amps of current. By adding a relay into the system the headlight switch would then carry just .05 amps of current, and all of the heavy battery current would stay down next to the headlight relay. Your headlights would then be brighter because the distance the heavy current has to travel is reduced by 2/3.

A headlamp that receives 95% of its rated voltage will only provide 83% of its rated output. A one amp drop in voltage at the headlamp...and the headlamp will provide just 67% of its rated output. Halogen headlamps will not fix this because they require 30 percent more current and you are short of current already.

Headlight Relays work because less distance means less voltage drop. With original headlight switches becoming difficult to find and expensive, It seems logical to also do what we can to save the originals

Symptoms....
As the contacts wear in your original headlight switch it causes the contact points in the switch itself to arc and burn. this causes high resistance (heat) which causes still more arcing and burning of the contacts. You begin to notice the switch getting hot and having to pull the switch off and on a couple of times before the lights come on. Those are the first signs of trouble ahead.

The headlight relay kits are a simple installation using the middle wire of the dimmer switch. The relay is very small and mounts down close to the battery on the inner fender or firewall. Installation time is less than an hour. Best of all you can see the difference immediately.

Headlight relays started appearing during the mid to late 1950's, beginning on cars, then later on trucks. A headlight relay will give you brighter headlights and greatly entend the life of your original headlight switch. A typical 6 volt headlight switch is expected to carry 20 plus amps of current.


Yes and no. A headlight relay only gives brighter headlights if it is hooked up to run both high and low beam filaments simultaneously instead of one or the other. Also, the system can handle more current if the wire size is increased, so brighter bulbs can be used. Switch life is increased.

By adding a relay into the system the headlight switch would then carry just .05 amps of current, and all of the heavy battery current would stay down next to the headlight relay.
Yes

Your headlights would then be brighter because the distance the heavy current has to travel is reduced by 2/3.

NO. The relay does not reduce the distance considerably. It does allow more current to be switched, allowing higher wattage bulbs to be used.


A headlamp that receives 95% of its rated voltage will only provide 83% of its rated output.

Close...
A one amp drop in voltage at the headlamp...and the headlamp will provide just 67% of its rated output. Halogen headlamps will not fix this because they require 30 percent more current and you are short of current already.

No. There is no such thing as one amp drop in voltage. Amps are current. Volts are voltage. Watts are power. Volts and Watts are lost in transmission if your wire is too small. Amps are not. An amp in is an amp out. Adding higher wattage bulbs and beefing up the wiring will give you brighter headlights. It will use more current for the same amount of voltage. Just a relay won't.

Headlight Relays work because less distance means less voltage drop. With original headlight switches becoming difficult to find and expensive, It seems logical to also do what we can to save the originals

A relay will cut down on contact wear, but will not make your lights brighter. Better wires will.
Symptoms....
As the contacts wear in your original headlight switch it causes the contact points in the switch itself to arc and burn. this causes high resistance (heat) which causes still more arcing and burning of the contacts. You begin to notice the switch getting hot and having to pull the switch off and on a couple of times before the lights come on. Those are the first signs of trouble ahead.

Yes. That is what a relay is for.


The headlight relay kits are a simple installation using the middle wire of the dimmer switch. The relay is very small and mounts down close to the battery on the inner fender or firewall. Installation time is less than an hour. Best of all you can see the difference immediately.

How does just adding a relay but keeping the dimmer switch wiring make the lights brighter unless your headlight switch is really hosed? It is a good idea, but I hope you aren't charging a lot for a $5 relay and some instructions. I also hope you are adding a fuse at the same time. I will send anyone a schematic diagram of how a headlight circuit works for free if they want, with and without relays.

[ 12-20-2001: Message edited by: 4ontheFloor ]

I want one of these 6V headlight relays. Unfortunately the email address [email protected] does not work, and, as a new member of this forum I am not allowed to personal message anyone on this forum. Where do I go to get one?

Max, Fifthave has not been active on the site since 2011, so you probably won't get an answer from him.

Please check in to the welcome forum and introduce yourself and what vehicle you are working on (year, make, model, engine, ect).

Also, please read the rules pertaining to buying, selling and trading in the forums. (Buying, selling and trading is allowed in the swap meet area).

Thanks,
Rusty Rod

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