So I have a couple of things I want to add to my truck and am trying to figure out how to do it without "hacking" the wiring. I bought the Dakota Digital gauge cluster and need to figure out how to wire that. I also bought a kit from LMC to add daytime running lights. I also planned to buy some seat heaters. Down the line I will certainly be adding air conditioning, but that probably won't be for a couple years. I considered various after market harnesses to completely rewire the truck and if I start having a bunch of electrical problems I can always decide to go that route in the future. But right now I feel that would be a big complicated unnecessary project. All of these add-ons, including the $800 gauges, instruct tapping into my existing fuse block. The DRL kit that I bought even comes with a little fuse tap made for the glass barrel type fuses. Maybe I'm being picky, but I just don't want to mess with the stock fuse block unless I'm replacing it with a Painless or some other fancy aftermarket block. Why not just go ahead and replace it you ask? It looks like kind of a hassle, I can't really find step-by-step hold my hand every step of the way type instructions, and right now stuff is working so I don't think I should mess with it. I came across a website where a guy explained how he added a new 12 fuse block for accessories. I think I want to do something like this, but simpler:



He split his 12 fuse block into two 6 fuse sections and wired power to each separately and through a separate relay. Instead of that, I just bought a 6 fuse block and will use a single relay and circuit breaker. But the general idea is the same. This guy was doing this in a Toyota with blade style fuse box and used an "add a fuse" to connect the ignition switched wire to the relay. I suppose I can do that too, but my main question is: What is the least "hacky" way to do it? Use one of these:


Or is there a convenient wire that I can locate under the dash or in the engine bay that I can solder my new wire to? I've heard a lot of negative comments around here about "hack jobs" and "prior owner" is like a four letter word. So what's the correct way?

 

So on Roadkill Garage there was an episode where they were building their Ford muscle truck. They added in a constant duty solenoid that had the capability of running 80 amps and provided a power point for battery hot and key on accessories. Said it would be great for adding on things like electric fans and lights. Looked pretty slick, may be worth looking into. Is that the kind of thing that your after?

 

The diagram you posted is correct and very simple. The one thing that is wrong is the circuit breaker should be a 30 amp. The relay should be a 40 SPDT and then make sure your loads combined don't exceed 80% of the 30 amp circuit breaker. This keeps all the wires within temp rating and allows the use of 8ga primary wire.

 

Do you think 40 amps would melt 12 gauge wire? The best relay for this I could find on Amazon was:




so primary leads are 12 gauge and the relay is rated as 50 amps. But I will have the 40 amp circuit breaker before the relay anyway. Funny that they would make a 50 amp relay with 12 gauge wire if that was problematic. It’s not just this one, but every relay I found. This was probably the least cheap. Since then I have found heavy duty Cole Hersey relays that are rated up to 200 amp, but those have posts that accept any gauge wire you want. A Bosch type relay on the other hand, I don’t think can accept heavier wire and is not generally meant for more than 40 amps. I realize it says 30 amps for the “normally closed” but I don’t plan to use that terminal.

Any opinions on the cleanest way to procure the ignition switched wire that I’ll need?