Need help with relay mod for headlights

[Turtle12400]

I'm trying to mod my headlights so low beams stay on when I switch to high beams, but the guide for doing that mod is really vague and not very helpful (THIS guide).

I'm not sure if I'm adding a new relay in or if I'm altering an existing relay. It doesn't seem like there's a relay for the headlights, so I'm really confused.

Some help with figuring this out would be super great, thank you!

 

[Curious Hound]

You are adding a relay and also a new fused power source from the battery. When completed, this mod will;

1. run the low beams normally from the switch

or;

2. run the low beams from the new power source when the high beams are turned on. This will use the high beam source to energize the coil in the relay for the low beams.

 

[Turtle12400]

This is already very helpful!

This is the wiring schematic that's provided:

So based on this I'm simply tapping into the existing circuit, leaving the circuit intact but wiring in the relay. So when high beams are flicked on, the relay flips from 87 going to ground to 87 going to 86, thus powering the low beam circuit? In that case I don't see why the battery power is needed, but I'm probably very wrong. Been a while since I've done stuff with relays...

Either way, what kind of relay do I need? A part # would be lovely.

Thank you!!

 

[Curious Hound]

This is already very helpful!

This is the wiring schematic that's provided:
View attachment 116411

So based on this I'm simply tapping into the existing circuit, leaving the circuit intact but wiring in the relay. So when high beams are flicked on, the relay flips from 87 going to ground to 87 going to 86, thus powering the low beam circuit? In that case I don't see why the battery power is needed, but I'm probably very wrong. Been a while since I've done stuff with relays...

Either way, what kind of relay do I need? A part # would be lovely.

Thank you!!

No. When the relay is energized, it sends power from 30 to 87 to power the low beams. The high beam power going to 86 energizes the coil (grounded by 85) and that is what closes the circuit from 30 to 87.

A relay is a switch, just like a light switch, except that instead of your fingers flipping the switch closed, it uses an electromagnetic coil to do it. 86-85 are the coil (your fingers) toggling the switch contacts 30-87 closed or open.

 

[Curious Hound]

Try this video, jump ahead to about the 20 minute mark where I discuss solenoids and relays.

 

[Turtle12400]

Okayyyy I get it now. That video was super helpful. Thank you so much.

So this relay would work...?

https://www.oreillyauto.com/detail/...-multi-purpose-relay/mpi0/2er13?q=relay&pos=0

 

[Curious Hound]

Yes. It will.

 

[Curious Hound]

Also, where that schematic shows an 18gauge fusible link, you could substitute a fuse holder and 15amp fuse like this. I would recommend 14gauge wire for your wiring. But no smaller than 16gauge.

 

[Turtle12400]

Okay I've got the harness opened up and I'm a little confused. The highs have one wire running to both, spliced just before the passenger side headlight. All good.

However, the lows have two different wires runing to each one, a grey wire for the passenger side and a purple wire for the driver side.

Do I run a wire out of 87 and split it and splice into the lows circuit? Like this:

 

[2011Supercab]

Just one of them, the purple or grey, your choice.

 

[Turtle12400]

All done! Works perfectly.

View attachment 116515 View attachment 116516
View attachment 116517 View attachment 116520

 

[alwaysFlOoReD]

All done! Works perfectly.

View attachment 116515 View attachment 116516
View attachment 116517 View attachment 116520

"The attached page could not be found."
Getting pics onto this site is a pain in the ass. It is not intuitive when using an android phone.

 

[Curious Hound]

Glad you got it.