where do you get your 12 volts?

I know that sounds like a dumb question, but what do you use to get +12V to all the sources that need it under the dash, specifically security systems? I've asked myself this several times. I'm installing a DEI 5806V in a 2015 Toyota Tacoma. By my count, I need 12 volts to at least 6 sources: the brain itself, the Smart Start module, the DBALL, H3/2, H3/5, and H3/9. How does everyone else do it? Side note: pretty sure I am not using H3/3 (pink/black). Am I wrong? Thank you!

Side note 2: I normally get my 12 volts from the ignition switch. But for 6 wires, I don't have a clean way of doing it.

Most of the time the ignition has a reasonable sized 12 volt that can run things like remote starter/alarm and bypass...now some vehicles you have to search a little harder due to the ignition being inadequate...most newer toyotas have tiny wires at the ignition so I use the "giant" fat white at the fuse box above the DKP...Chevs I go to the bcm it's just one of those things...and for high current stuff I'll go straight to the battery...fused of course within 12 inches of the post! Tech info generaly lists the best place to go and your trusty volt meter will help you find those big juicy 12 volt connections...always meter and be sure that you have your mains fused...be safe!Solder, tape, repeat!

Got it. But how do you connect 6 wires to 1? It's either daisy chaining butt connectors or the worlds largest solder joint as I see it. Is there a better way?

uranium235 wrote: Got it. But how do you connect 6 wires to 1?

I use uninsulated butt splices for multiple wire junctions. Either same size, or step-down. Use a size suitable for the combined wires' size. Sometimes you can loop-back a couple of wires to go in the opposite end of the splice from where they originate. Or put the biggest wire in one end, and all the little wires in the other. Be creative so that you get a good crimp on each end, and tug on the wires when finished to QC the quality of the crimp. I like the uninsulated because the insulated sleeve doesn't get in the way, you get a better crimp, and you can solder the finished splice if you have a big enough gun. I use heat shrink tubing to insulate the finished splice.

well you are over thinking..the remote start is the work horse that requires two 12 volt connections that will be fused to 30amp..the bypass is usually piggy backing off of the remote start via data cable and the smart start is very low current and can also feed from the RS by simply tying into one of the power leads....you're over complicating your install...furthermore the power wires for smart start and bypass are tiny and barely noticeable in a solder joint...even with a dozen of them it would be managable to solder. (Never use butt connectors!!!!). We are not talking a of huge current draw on the system....would you make 6 30 amp connections to one line...hell no...but these are not that kind of beast...find good solid "juicy" power lines and use Em...if you need more juice go to the battery...don't over think the process. As for the h3 stuff Im an auto start guy I don't deal with viper unless I have to, but two good 12 vt sources will hook up any RS, bypass, and smart start on the market today in just about any vehicle. :)Solder, tape, repeat!

You can also use a "Western Union" splice and solder and heat shrink it. I use this technique for multiple small gauge wires where the combined size of all the wires isn't more than 14 gauge from each side of the splice. Bigger than this becomes unwieldy, difficult to solder, and ugly, so I use the crimp butts described above.

Dave! Western union is a great connection...I do a modified western union for tapping into wires as well which makes for a great connection that never will fail. Solder when at all possible...:) but as Dave said in situations with large gauge I also use uninsulated butt connectors and solder them once crimped...rarely if ever do I need to do this though...but I. Those long runs of car that all need to find a 12 volt source it's an option.Solder, tape, repeat!

Never use the butts, even the large gauge R/Start wires, I use solder and heat shrink, say wires on a DEI unit including the red at H1, solder as a "Y" joint 2 at a time until I have 1 red or if multi "thick" wires e.g. some earlier BMW, Toyota I'll bring two wires, one to each constant or as Shark says especially Toyota and some Hondas the main battery feed to the fuse box. Just as a point when you have thin gauge wires at the ignition such as Toyota, Ford etc., I change that awful quality H3 wiring for thinner gauge I've recently done quite a few installs using CAN modules such as DBALL2 using a single 10 amp fuse.

agree with Howie...I also step down the heavy gauge wires all the time when going to tiny ignition wires at the column...I have clot matched rolls of wires for my main harnesses and it makes for a neater install. Not to mention that it prevents fighting with the shroud on reinstall because you have l these giant gauge wires in the way of some tight fitting shrouds...I use this particular method on nearly all Chev trucks for ignition and accessory...:)Solder, tape, repeat!