Best way to tap into ignition for a hot wire

[r2m]

I'll be installing a dual battery isolator within the next day or so and I need to run a wire to my ignition so the isolator turns on with the key.

Question: what/where is the best place to tap into the ignition?
If possible, please give a good description, don't just say under the dash by the steering wheel... That part I've figured out.

** NOTE: I don't want to just stick a wire into the fuse box next to the fuse, I would like this to be clean and professional (as possible) without tearing out my dash.

Thanks in advance to all responders!!

 

[Fallon 40]

I went to my local stereo shop near work and they tapped into a hot wire for me.
Their wire taps were much higher quality than you can buy at the local auto zone/ Napa store.
Took them ten minutes.

 

[r2m]

I'll be needing to pull the wire through the firewall also. This isolator will be under the hood by the batteries (drivers side, front).

 

[Fallon 40]

No worries with a good stereo shop,they installed grommets in my firewall as well and I ran the wire through. I showed them the wire I wanted to use and they did the rest. Much cleaner than I could have ever done and ten times faster.
I did this for my 2 gauge battery wires and my locker wires.

 

[Sandroad]

You may have already found this thread in the FAQs. I'm not sure it will help, but from my quick look it might be worth a read-through for your tap info? The only wiring I've done under the dash was for a trailer brake controller using an existing plug.

https://forum.ih8mud.com/threads/accessory-relay-always-on-power.86714/

 

[rusty_tlc]

I think I pulled my ignition hot wire off the main fuse from an option not installed on my truck. Anything that went through the fire wall goes through the rubber boot with the OEM wires sealed with a little silicon.

 

[hoser]

I'd check the main fuse block next to the battery. There's likely an unused AHC fuse spot. If you use that, you won't need to run anything new through the fire wall.

 

[r2m]

^ Good point about checking the fuse block under the hood! I'll give that a look.
I'll use my multitester to see what's hot and what's not when the key is out.

 

[OregonLC]

^ That's where I tapped for my BlueSea isolator.

 

[spressomon]

Yeah it's tempting for sure because they're quick and easy (the first time ) but DO NOT use nor let anyone else use Scotch Blocks to tap power!

 

[OregonLC]

What do you use?

 

[hankinid]

What do you use?

A seamless crimp, a calibrated tool designed for the crimp, and adhesive-lined thinwall heat shrink to cover. Similar to stuff used in military aircraft.

Steve

 

[OregonLC]

A seamless crimp, a calibrated tool designed for the crimp, and adhesive-lined thinwall heat shrink to cover. Similar to stuff used in military aircraft.

Can you post up a link? Not quite picturing what you're referencing.

 

[hankinid]

Sorry for the unbelievingly long response time...I check alerts daily and one for this thread just showed up.

Link here...http://www.ttiinc.com/object/fp_tyco_splices

 

[ihadmail]

@hankinid if you're tapping into an existing circuit to pull power from it, do you just put two wires on one end of those splice connectors and one wire on the other end?

 

[hankinid]

@hankinid if you're tapping into an existing circuit to pull power from it, do you just put two wires on one end of those splice connectors and one wire on the other end?

Correct...as long as the wires on each side of the splice are within the size (awg) range of the splice.

Steve