Electrical newbie trying not to burn down the truck

I've been reading through the various electrical threads on here, and looking at youtube videos, to try and wrap my head around what I need to do from a wiring standpoint to install a group of accessories:
- heated seats
- fog lights
- light bar (eventually)
- gmrs and cb radios
- aux battery hook up (ideally two, one in the cab and one in the bed)

Now I'm not doing all of this right away, and I think I now understand the value of relays for things that need switches to operate them (like the lights and heated seats). But where I'm confused is on things like radios that just need power (right?).

I was originally planning on doing just a aux fuse box, but then I read about the relay stuff, and started looking at the whole integrated relay fuse box option.

Is the best solution to run both an integrated relay fuse box, AND an additional separate fuse box for things that don't need cab switches? Am I over thinking this?

 

The way I understood electrical in the most simplest of terms is (and I’m sure there is more experienced sparkies out there)

Does the powered object require a lot of wattage?
That includes: Winches, air compressors, halogen lights, heated seats.
Then that item will need the following:

• Relay (rated)
• Thick AWG wiring (rated)
• Switch
• Fuse (inline or block)
• Etc.

If it does not, then you can go straight to a switch instead.
This can include:
LED lights if any kind, marker lights, low wattage halogen lights.

If I were to recommend a place to start so you can understand and educate yourself by experiencing it.

Start with some LED light bars, or something low wattage. That way as you learn, you can understand how to wire your object up, and what it needs.
You don’t need to add a relay or fuse block for everything.

The beauty of LED or anything low wattage is that you can use a in-line fuse, and hook up directly to a switch.

Just remember more wattage = more risk = more protection.

 

If you build or buy an appropriate aux panel, it will have both relay switched and constant fused circuits.

Your seats and radios can easily be powered with an Add-a-Fuse installed in an appropriate circuit inside the cab. The heated seats are almost certainly 5A or less, ditto the radios (each). These would not need a relay if using an appropriately rated switch.

Your truck may also have the wiring in place for fogs, which would mean simply installing a switch in the OEM location and plugging the fogs in to the factory harness, as well as possibly installing a relay into the factory fusebox in the correct location.

The additional batteries will require large (1/0 or larger depending on length of run) wiring, and I'm not sure why you would want one in the cab as well as the bed. You will also need to modify the factory battery wiring to accommodate aftermarket battery terminals to accommodate the additional battery wiring.

A couple of the seemingly small things that make a huge difference when comparing shitty electrical work vs. acceptable or even pro electrical work are, in no particular order:

- quality of wire (sized appropriately for amperage and distance)
- quality of connectors (fully insulated spade terminals at a minimum)
- appropriate grounds (dedicated, common grounds for all added devices)

Buy more wire than you think you will need, buy extra connectors, and get a quality stripper and crimper. Practice stripping, trimming, and crimping until you're comfortable with it and have figured out your tools before you start on the actual project. Plan where the wires will run ahead of time, and run all the wires together in bundles whenever possible, neatly taped and/or loomed.

 

Personally, I prefer to keep all my added electrical circuits separate from the vehicles wiring. Build yourself an auxiliary power panel and route all your accessories through there. Here is a good start. But in a nutshell, you'll pull directly off your battery through a fuse or circuit breaker to your aux power panel. The fuse or breaker should be rated for your wire gauge first and have enough rating for all your accessories running at the same time. From your power panel you'll pull through a fuse to whatever system you want powered and return to one of your vehicle grounds.

-J

 

Don't forget to properly fuse the circuit - always!

 

Thanks ya'll. I appreciate the feedback. I was originally looking at doing a fuse panel like a Blue Sea, on a separate plate under the hood, but I saw mention of needing relays, and that doing an integrated relay/fuse block was better than a Blue Sea and a couple of external Relays. So I found the DIY bussmann thread, which is what put me down the whole rabbit hole. I want to use factory switches rather than a switch panel, but if I don't need to use relay's on things like heated seats or possibly the radios (I don't need switches for these, I just want them to get power when the car is running), then maybe I can just run a couple of relay's for the items that need them, rather than builing the bussmann (which looks cool as hell, but my mind might explode if I have to build that).

The reason I want to run aux battery connectors to both the cab and the bed is because I'm building a small portable power station / battery box. For some trips I'd like it in the cab with me, and other times stored in the bed with other gear it'll be powering. I figured having two places to connect, with Anderson connectors, would be the easiest an safest way to do it (maybe with a breaker or switch to decide which one is getting power?).

I've handled/rebuilt wiring harnesses for motorcycles, so I'm familiar with the basics, but I definitely appreciate the thoughts on connectors, wires, and tools. I've been reading about wire size = resistance and distance, and it seems like it's whole other skill to wrap my head around.

 

Relays are necessary under higher amp loads. The reason you would want to use them is that you can keep the power feeds in the engine compartment and run a much smaller gauge wire through the firewall to the switch. Each switch would only require 1 wire per circuit as the ground wire for the switch can terminate in the cab at a vehicle ground. For example, your switched power side of the relay would have your 10-12 gauge wire but the coil wire (pin 85/86) would carry on a much less expensive 14-18 gauge wire through the firewall grommet and into the cab. I hope that makes sense? I dont personally run this but others have run the SwitchPro 9100 which may make your wiring woes a bit more manageable. If I remember correctly, theres just a small wire bundle that runs through the cab to the illuminated switch panel. People have mounted them near the cup holder cubby or next to the shifter for a clean look. With the bussmann setup, you can get the mini relays that fit into the block for a clean look too. Basically, you have a few options.

-J

 

Yeah, the bussmann set up seems like the ideal (I don't want to run something like a SwitchPro). It just seems like it a rather serious undertaking to build it right.

 

The way I see it is, you're learning a new skill. Also, in the event that you need to troubleshoot an issue down the road away from technology, you at least have an understanding on how everything works. It can seem daunting at first but if you break it down to smaller purchases, it can make it less of a hit to the wallet. Do you absolutely need different colored wires for your bundle? Not really, if you label the wiring with markings understandable to you, you can get away with just 3 colors. White, Red, and Black. The colors only make it easier for someone else to troubleshoot. To put it this way, the aircraft I work on all use white wiring for everything. 50 wires in a bundle? All white. Have fun with that. Anyway, before I trail off - buy your wire one month, next month buy the connectors and heat shrink, month after pick up the tools, etc... Then trace out your pin-outs on a piece of paper and construct it to that. Put on your favorite podcast or something on TV while you build it at your table. Follow the link to the bussman I posted above as it's fairly straight forward with everything you'll need. Obviously, tailor it to your needs but having extra fuses and mini relays in unused ports will help you in the event something blows. You can do it, you just have to believe in yourself and just do.

-J

 

If you want a very gory jump into wiring these trucks, check out my ongoing thread on wiring here.

It's a little chaotic and there's a ton of stuff in there to try to fully understand all at once, but I've touched pretty much every piece of wiring in this truck from the Big 3 through the fusebox and into the cab and bed, and I've added quite a lot of custom wiring including a relay box.

If nothing else it's something to read while you drink your coffee and will give you a peek at what's there, what can be done, and where and how.

The thing that isn't necessarily obvious is that there IS an overarching plan, and I started with a complete end goal in mind and started at the foundation. Doing it this way, which it sounds like you are, will save you a lot of time, money, and labor, even if it means not having the cool factor up front while you take care of the infrastructure.

If you're planning to put in a higher output alternator, some of the info in there will be very helpful, although one or two details will be different, particularly with the Big 3 wiring. There is a lot of discussion about that, including the method for a larger alt, in that thread but the details are a little muddy in places. The main difference with a larger alt is going to be that you'll have one additional run (which I do not) from the alternator to the battery, which will have its own separate fuse based on the output of the alt.

 

Awesome, thanks. Yeah I'm trying to do it 'right'. My friends and I wired up a rear camera to go with the joying head unit we installed, and the process was/is janky. I'm used to motorcycles where I can see the whole loom and add something to it, or remove something, and feel like I haven't done something questionable. But when the instructions called for taping into the reverse lights I suddenly felt totally out of my depth.