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I am wanting to wire up my lightbar on a 3way switch so that I can have them on when the highbeams are on, off, or on independently. I know i will need a relay and was wondering if anyone could help me with a wiring diagram so I know what all wires to hook to the relay. Do i need 2 relays or just one for the highbeams?
You could use an LED relay harness that has an off/on switch and is independently powered, then use a relay to control whether it's on or off using your hi beams as a trigger.
This is a good harness for $30. I have used one of these before.
Seems like you would need a single pole double throw (SPDT) On-Off-On switch, a relay and a diode.
High beams would go to the switch with a diode to prevent power back feed. then another power source on the other side of the switch. Feed this to the coil of the relay. wire the other side of the coil to ground. Then wire a thick power wire from battery to pin 30 Common and the light bar to pin 87 Normally Open
Sorry, I can't draw it, but it's not that complicated.
FIND yourself a decent waterproof relay. IGM on Amazon for $15.
FIND yourself a three position switch; OFF, ON1 and ON2. IDK what it's called, but you need 2 INs and 2 OUTs.
PLAN your circuits, HIGH side and LOW side.
The HIGH side runs the lights directly from battery via the relay. Use appropriate size wire and install a fuse at the battery. There are charts on-line which show what size wire to use for DC circuits.
The LOW side turns the relay on and off. I call it the "low side" because it's only draw is the tiny magnet inside the relay.
Function1, ON with HI beams - You'll need to find a place to tap into the HI beam circuit to activate the relay. This power goes thru the cab switch, then to the relay. If you have LED headlights(like I do), IDK how this is done. If you have old school headlights, I assume the harness is the same and easy to tap into.
Function2, ON any time - Wire the second position on the cab switch with 12 volts then (also) to the relay. You can wire a DIODE on both sides of the relay input to prevent backfeeding the switch, but I'm not sure it's necessary.
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My Reverse Lights - run ON/OFF anytime, or ON with reverse gear.
I wired a fused lead from battery to a switch inside the cab.
OFF, ON1, ON2.
ON1 - feeds my relay which is activated by a tap-in from the trailer harness reverse light circuit.
ON2 - bypasses the relay and powers the lights directly. This mode backfeeds the cab switch. I didn't care in this case. I could have wired a diode to prevent this. I did so when I wired dad's extra loud blinker piezo noise maker, otherwise I would have backfed the opposite side.
I put all the connections inside a outdoor electrical box mounted under the bed, so it's all high and dry.
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My Driving Lights - run ON/OFF anytime, but also via a foot switch. So, when I turn the cab switch ON, I activate the lights with a foot switch on and off like your dads 70's car. It seems like extra work, but they are so bright I have no need of OEM high beams.
I bought a set of Baja Designs XL80s. THEY ROCK! If you want the brightest lights out there, get them. When they are on, I can turn off my OEM LEDs and barely notice it. Yes, they are pricey, but they are great. Also, they fit into the fog light pocket space. Baja makes a mounting pod for them too. I got the XL80s which are their highest wattage. If you go for the lower wattage XL model, they are plug and play with the OEM fog harness. Then you can use FORScan to get fogs + HIs together. They'd still be on when you switch to LOWs though. https://www.f150forum.com/f83/what-l...5/#post5266762
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Be sure to protect all the exposed wires. I used split plastic wire loom. It was pretty cheap on Amazon and EXPENSIVE at the local auto parts store or Radio Shack. Also, most didn't have it. I sealed all of it with electrical tape. A PITA for sure, but there's no water inside my stuff.
TomJV
that has two 87 pins instead of the normal 87 and 87a pins.
Connect one 87 pin to your aux lights, the other 87 pin to your switch. Connect the high beams to pin 86 so that the relay is also triggered when the high beams come on.
Here's KC's wiring diagram. This is for their reverse light kit, but the relay is wired the same.
To be extra safe, put a diode on the line coming from your high beams.
Buy a KC HiLites 330 relay that has two 87 pins instead of the normal 87 and 87a pins.
Connect one 87 pin to your aux lights, the other 87 pin to your switch. Connect the high beams to pin 86 so that the relay is also triggered when the high beams come on.
Here's KC's wiring diagram. This is for their reverse light kit, but the relay is wired the same.
To be extra safe, put a diode on the line coming from your high beams.
Can someone give specifics on what diode to use? Thanks in advance!
Can someone give specifics on what diode to use? Thanks in advance!
d
Just use a relay with a diode built in. They pretty much cost the same as relays without the diode. You can buy diodes for under $1.....but why go through the trouble when you can get it already in the relay.
I did this install, for some lights on my truck. Mine was a bit more complicated, but the wiring is the same. I will add that I first considered having the ability to run my aux lights with the headlights off (like you), but in the end I realized that I’ll never use them without he headlights on...so my decision eliminated the added complexity of a feature I’d not use. If you think harder and realize you won’t need the aux lights on without the headlights, your wiring will be easier. You can then use a single simple on/off switch in the cab.
Here is one on Amazon, with built-in diode...note, the $15 is for 2 of them.
Link:
06-08-2017, 09:10 AM
Lightbar Wiring Help!! 3-Way Switch
