Path of wire out of fuse box under the hood?

[WCVanHorne]

So I've been though lots of mod threads but haven't seen or have missed exact illustrations of alternatives for routing a fuse tap wire out of the fuse box under the hood.

Several nice secondary fuse boxes if one is going to go all out adding accessories but I'm probably just doing the one cct for the foreseeable future.

As I didn't want to hijack a build thread or perform thread necromancy I'm posting this new one just to see if there are any alternatives suggested.

My current plan, which you can pretty much see in the photo below, is to drill a small hole in the side, just below the lid lip, in the well formed by the bolt. I will then put in a rubber grommet small enough to get a reasonably water resistant fit around the 14GA wire I will thread through and run to a relay.

Any other ideas? Warnings? Suggestions?



Note the blue crimp on the red wire off the is not used. I will be clipping it shorter and splicing on the end of my wire run out to the relay. It is just lying there for fitting and planning.

 

[Engineer]

I don't see any problems with your outlined plan but if it was me I would put a ring terminal on the end of the power wire and have an inline fuse harness ( I think you can buy these, essentially what comes on every accessory wire harness. This unit will be fused and it keeps you out of the factory wiring. Granted the style of fuse tap has been used for years without issue but if possible I would stay out of the factory wiring and it would prevent from having to drill or modify the fuse box.

 

[TrkyMfns]

I agree with what [MENTION=96008]Engineer[/MENTION] said. If possible, I always prefer to leave the stock fuse box alone.

 

[DEERUNNER]

How about just using the in-cabin fuse panel for your tap? What device are you planning to power using a tap?

 

[Antman]

I don't see any problems with your outlined plan but if it was me I would put a ring terminal on the end of the power wire and have an inline fuse harness ( I think you can buy these, essentially what comes on every accessory wire harness. This unit will be fused and it keeps you out of the factory wiring. Granted the style of fuse tap has been used for years without issue but if possible I would stay out of the factory wiring and it would prevent from having to drill or modify the fuse box.

^^^Exactly this. There is zero reason to tap into the fuse box under the hood. Every connection in there is hot all the time (not ignition sourced).

Run a ring terminal to the battery and use an inline fuse. Done.

 

[rigtec]

Hi [MENTION=85758]WCVanHorne[/MENTION],

Whenever I'm adding an electrical accessory to the truck I'll 'deliberately' avoid cutting into factory wiring in the fuseboxes because, #(1) There's no reason to cut into or disturb the tightly routed o.e.m. wiring bundle(s) path. And #(2) like [MENTION=96008]Engineer[/MENTION], [MENTION=65614]Antman[/MENTION] and [MENTION=130190]TrkyMfns[/MENTION] have offered... incorporating an Independent, properly sized 'in-line' fuse off of a main (POS) battery terminal aux (imho), is far better than 'Hitch-hiking' an existing, preloaded oem circuit fuse whenever possible.

'just my 0.00002 cents!'

 

[WCVanHorne]

I think there is some confusion here. I am *NOT* tapping into any factory wiring harness. For all the reasons given. However I am using one of the unused fuse positions in the factory fuse box under the hood. This is identical to what people do all the time under the dash in the cabin. However I am powering lights outside the interior cabin and it would be a long and pointless run though the firewall; hence using the fuse box under the hood.

The external terminal on the battery is arguably messier in terms of scattering fuses about and having more wiring and a "loose" fuse exposed under the hood. Yes I know you can get inline weather proof ones but why not put it with the rest of the fuses and keep the unfused wire segment essentially non-existent (best practice).

Essentially this mod could be completely undone with a piece of tape over a tiny hole in the fusebox.

 

[WCVanHorne]

^^^Exactly this. There is zero reason to tap into the fuse box under the hood. Every connection in there is hot all the time (not ignition sourced).

Run a ring terminal to the battery and use an inline fuse. Done.

This is hot all the time too. You had just suggested this was bad in the previous sentence but this is what quite a few mods need.

As I mentioned, unless you are making a major new distribution (as you have done), I think one more small fused circuit should be tucked with all the rest of the fuses in the factory weather resistant box. Protected, easy to find, no unnecessary, unfused wire segments.

 

[Antman]

This is hot all the time too. You had just suggested this was bad in the previous sentence but this is what quite a few mods need.

As I mentioned, unless you are making a major new distribution (as you have done), I think one more small fused circuit should be tucked with all the rest of the fuses in the factory weather resistant box. Protected, easy to find, no unnecessary, unfused wire segments.

I think you missed my point completely.

 

[rigtec]

This is hot all the time too. You had just suggested this was bad in the previous sentence but this is what quite a few mods need.

As I mentioned, unless you are making a major new distribution (as you have done), I think one more small fused circuit should be tucked with all the rest of the fuses in the factory weather resistant box. Protected, easy to find, no unnecessary, unfused wire segments.

Hi WCVanHorne,

The 'quoted' statement below is completely on point...

@Antman said: "....There is zero reason to tap into the fuse box under the hood..."

...particularly when you consider how little there is to be gained by breaching/altering it's intended OEM purpose, and how much is involved in 'properly' adding a new circuit to it's already limited vacancy availability. If it's just a matter of aesthetics or pride of workmanship... there are a variety of electrical wiring accessories online e.g., amazon, ebay..., to keep things looking neat and professional.

Just out of curiosity... what kind of modification or add-on are you working on?

Rgds!

 

[WCVanHorne]

Ok so I am really not getting the hate on for this.

Antman: I have the utmost respect for your work. Your varied and ambitious mods are an inspiration to us all. However I don't know if I missed your point. If I were adding lots of ccts under the hood, and/or some pretty high draw ones like a compressor, than tapping more directly onto the battery with a secondary fuse box distribution would certainly be the way to go (again like you did). However for a one off, what is wrong with tapping into the fuse box? There are probably a half dozen or more spare slots. This is exactly what you and others have down under the dash, eg.:

http://www.toyota-4runner.org/5th-gen-t4rs/92013-antmans-thread-4.html#post813452

Other than routing out of the box this is the same thing. A tiny, discreet hole and nice water resistant grommet are arguably no worse than going though the firewall, taping into factory wiring, etc. The usual mod stuff.

Sure I could keep it all by itself with an external fuse and directly off the battery, however by similar reasoning why didn't you come from the battery in the aforelinked mod? I suppose your point could be that there is inadequate diversity in the feed to the fuse box under the hood to support another <10A but I don't think so given all the other high draw, cycling, and intermittent loads. That's probably the only reason I can think of and, as I said before, if this was significant I would definitely go direct.

 

[Its-a-4Runner]

Sorry old thread, but just confirming if I'm missing something?. Im using an "add a circuit" into an existing high beam fuse to trigger my light bar when the high beams are activated. This is NOT always hot as stated. Only gets power upon stalk activation.

Sent from my STV100-2 using Tapatalk

 

[magistersmax]

You'll be fine, I'm not sure why there was so much controversy in this old thread. Just be sure to route the wire in a way that keeps the fuse box watertight.

IMO add-a-circuits are the best way to add one tap without permanently messing with your wiring harness. If you end up needing power for additional accessories, then consider a secondary fuse block.


Sent from my iPhone using Tapatalk

 

[jrandom]

Most of the concern lies within how sensitive the system has become over the years. Hacking into anything willy nilly, not so recommended any more.

It certainly depends on what you are trying to achieve, grabbing a signal for a trigger sure, you're not going to be able to easily get it any other way, as you mentioned. Powering something or running a complete subsystem off of it, you're f'n silly, better built isolated.

 

[Jono.ful]

Sorry old thread, but just confirming if I'm missing something?. Im using an "add a circuit" into an existing high beam fuse to trigger my light bar when the high beams are activated. This is NOT always hot as stated. Only gets power upon stalk activation.

Sent from my STV100-2 using Tapatalk

Are you doing this through a relay, or are you using the high beam fuse slot with an add-a-circuit to run the light bar directly? I would want to know that the fuse slot and high beam relay were rated for the high beam current plus whatever the light bar pulls before I did that.
Would be much better to tap into the high beam circuit then use that to trigger a separate relay and inline fuse which would in turn power the light bar rather than piggybacking off the headlight fuse slot and associated relays and expecting them to handle double (or more) current than they were intended to

 

[supratt]

Are you doing this through a relay, or are you using the high beam fuse slot with an add-a-circuit to run the light bar directly? I would want to know that the fuse slot and high beam relay were rated for the high beam current plus whatever the light bar pulls before I did that.
Would be much better to tap into the high beam circuit then use that to trigger a separate relay and inline fuse which would in turn power the light bar rather than piggybacking off the headlight fuse slot and associated relays and expecting them to handle double (or more) current than they were intended to

yup, pulling my power directly from the battery. I have a relay that receives the 12v from the trigger wire after the high beams are on, which turns on the 32" light bar. I don't feel I need a 3 way switch at the dash for my application. I want all my lights on at once when I safely need them and won't need just the light bar or high beams on independently. My HID's with the clear/spaced lenses light up the road very nicely for night driving already.

 

[Jono.ful]

You should be fine then

 

[bocita1282]

Help with secondary fuse box

Sorry guys, only my second post. I appreciate all the threads and install directions. I have learned alot from this forum. However, I am having trouble with my auxillary fuse box install and can not find the answer on any thread. So, I bought the fuse box from ebay. Great box and made with quality. My fusebox came with a pos ignition cable I assume you connect to the battery? My problem is when I connected the pos ign cable, lightbar, and switches, the switch lights remained on without my key in the ignition. Any suggestions on how to fix this? What am I missing? I have mictuning push switches OEM style. I used a add a circuit to attach the green wire to the interior fuse box. I would like to connwct the 2nd red wire but I don’t know where to? Any help would be appreciated.