Accessories wiring Help

[oberah]

Happy new years Bitog community!
I am interested in wiring two or three sets of lights, and one or two additional accessories in my F150. I don’t want to have multiple wires coming off the battery, so an accessory fuse box under the hood Seems like a great option.
My question is regarding power to the switches in the cab. In the past, for one or two accessories, I have used fuse taps to the main fuse box however, I don’t want four or five fuse taps for this project. Is there a alternative for in the cab that I can use to power the switch itself?
Thank you for your help!

 

[Chris142]

Take power from the battery . Put the lights on relays under the hood and use the switch as a ground for the relays only.

That way you are not running voltage into the cab.

 

[ctechbob]

Take power from the battery . Put the lights on relays under the hood and use the switch as a ground for the relays only.

That way you are not running voltage into the cab.

Second this.

That way if one of your switch wires happens to short, the worst it will do is turn on the relay.

Decent little fuseblocks can be had for reasonable money that will distribute the power and fuse the circuits.

Something along the lines of this, although I have one for some minor circuits in my camper, I'm not sure how waterproof it would actually be. If you're mounting under the hood, find one that's good and sealed up since you're in a salt belt area. Get some good glue lined heat shrink to cover any connections you might make.

 

[oberah]

chris and ctechbob, thank you for the quick responses! In the past, when I have added a light bar with a relay, my wiring has used position 86 on the relay to the switch in the cab, and the physical switch gets power from the fuse box. Power from the fuse box was obtained through a fuse tap. Sounds like both of you are recommending something different, any chance you can spell it out step-by-step on wiring the relay to the switch? Thank you for the help.

 

[Chris142]

I would not go tapping into fuses. Today's computer stuff can be easily damaged by a short or a spike. Plus you are adding a load to a wire that feeds that fuse and it was not designed for carry extra currant.

Even things like head light circuits and dome lights are often ran through an ecm,bcm etc.

I would come off the battery to an added fuse block, put your relays close to the fuse block, wires to lights and just the trigger to the switch .

 

[eljefino]

Depending on the year of the truck the starter solenoid or alternator post may be a cleaner place to grab your power from. I agree on using maybe around a 10 ga wire to feed a mini fuse box to feed the lights. (Or use a thermal breaker that self-resets, lights are important.)

The only reason I'd tap the inside fuse box is to get ignition switched power, so you don't accidentally leave the lights on. Even then you can tap the fuse for ONLY relay coil power, which is miniscule, and you can tap the battery for actual light power. I like using something like the heated seat fuse, which is only on during RUN, and "mutes" when the key is turned to start.

 

[mk378]

You can buy it already made: a block with fuses integrated with a relay for each circuit after the fuse. Very commonly used for off-road lights.

 

[Sequoiasoon]

Guy on Piloteers wired up a MicTuning 8 gang switch box. If I had a lot I was doing I might look into it.

My Fogs/driving etc are toggle switch with relays as described. I run the ground wire from 85 or 86 and the trigger is my parking lights or high beams depending what I'm doing.

MicTuning P1S

 

[Sequoiasoon]

Here are 2 linked threads where I described the same thing and has links for relays/wires and diagram if you want to run separate.

https://bobistheoilguy.com/forums/threads/foglight-wiring.389961/post-7083061

https://bobistheoilguy.com/forums/threads/adding-fog-lights-and-unable-to-find-the-correct-fuse.389198/post-7062680

I don't know what your F150 has or what year but we have F550 Superduty Ambulances with I think 6 or 8 overhead aux switches pre setup. This is from F150 link https://www.fordservicecontent.com/Ford_Content/vdirsnet/OwnerManual/Home/Content?variantid=4706&languageCode=en&countryCode=USA&Uid=G2030305&ProcUid=G2030306&userMarket=usa&div=f&vFilteringEnabled=False&buildtype=web#:~:text=The%20auxiliary%20switchboard%20on%20the,for%20connection%20of%20electrical%20accessories.

and a video on them