Relay mod 4 headlights- circuit breaker?

[SunSoaked]

I'm in process of putting the headlights on relays. I'm pretty sure the factory has a circuit breaker in the circuit. So is this feature lost in the conversion? It would only be protecting the low power control wires to the relays. Should I add breakers on the load side of the relays? Seems goofy since the relays are within a foot of the battery now.

[Andy4639]

Originally Posted by SunSoaked

I'm in process of putting the headlights on relays. I'm pretty sure the factory has a circuit breaker in the circuit. So is this feature lost in the conversion? It would only be protecting the low power control wires to the relays. Should I add breakers on the load side of the relays? Seems goofy since the relays are within a foot of the battery now.

If you tied into the main wire at the battery past the fender mount you have the fusable link in the wire already but if you tied straight to the battery I'd put a 40 amp breaker in line.

[VetteVet]

Here's two diagrams to help you out.

The first doesn't give a value but a 20 to 30 amp fuse or circuit breaker in each circuit should be plenty.

The second shows a 20 amp fuse.







Using the Oms law calculator, if you are pushing 100 watts per headlight at 14 volts, you will have 9.8 amps in each light, so double that is 20 amps for the circuit. If you used a 30 amp fuse in each circuit you would be safe.

[SunSoaked]

As always, thanks VetteVet!

[VetteVet]

Originally Posted by SunSoaked

As always, thanks VetteVet!

You're welcome but I just illustrated what Andy said.

[SunSoaked]

I wired it just like the 2nd diagram except I used 16 guage fusible link instead of fuses. Funny how Napa sells fusible links with a ring terminal for $7 or you can buy a spool of link for a dollar more. Lol

[damnyankee36]

On that second diagram, wouldn't you rather consider using circuit breakers instead of fuses for safety purposes? At least if an overload occurs you won't completely lose your lights.

[SunSoaked]

The breaker is in the light switch. After the mod, it only controls the relays. The hi/low are now on separate circuits. If one shorts, just hit the dimmer switch. I used fusible link cause it's more reliable and less clutter.
The difference is night and day I might add with the H4 bulbs and relay mod.

[beaterku]

Here is how I have wired them in the past. Getting ready to wire my truck this way as well. I put a 30A fuse/breaker on the power feed. Wiring this way will not allow the low and hi to be on at the same time.

-Nick

[dfosh]

Is this for a GMC ? Thanks

[SunSoaked]

Originally Posted by dfosh

Is this for a GMC ? Thanks

Uhhhhhh....no.

[dmjlambert]

On a 4-headlight system all you do is run extra wires to power the inboard high beam lights in parallel to the high beam filament on the outboard hi/lo beam bulb. So the relay wiring is the same if you have wired the bulbs together.

[dfosh]

Thanks for the info . I just miss read the question when it was posted.

[Woodsloafer]

Subscribed

[beaterku]

I used the wiring diagram above to wire up my hi/low relays. One feed wire running to a 30amp fuse. You can see the heavy red wire jumping from one relay to the other.

[dmjlambert]

beaterku that is some really neat wiring. Better than factory.

[The Rocknrod]

Could fused relays work? https://www.ebay.com/itm/12V-DC-40-3...MAAOSwuLFZw09j

[beaterku]

Originally Posted by dmjlambert

beaterku that is some really neat wiring. Better than factory.

Thanks. I am a bit anal retentive. I also have 3 relays on the pass side for fans and fuel pump.