I see two types of blue pieces. There are blue butt connectors to connect two wire ends together, and there are blue wire taps. The wire taps allow you to tap into the electrical current of another wire without cutting it. You pop your new wire into the inside end, and then put the other side over the existing wire. Then you mash that metal spade down in the middle with a pair of pliers. The metal spade goes through the insulation and creates a circuit between the new and the old wire. Then the little plastic flap closes over it to cover the exposed end of the metal spade.
Kurt
Thanks, that's actually really cool!
On those piggyback connectors Kurt just described:
They are a bit unreliable, and most folks prefer to solder, but if you are going to use them, just install them meticulously and then insulate them well. If the top flap pops open, you have an electrically 'hot' chunk of metal exposed to the world. Also, those connectors are even less protected from the elements than crimp type connectors, so sealing them up will prolong the viability of the connection and slow corrosion.
I squeeze a dab of silicone in the ends, and then wrap a bit of electrical tape around it to keep the top flap from coming open. I mainly do them this way because these things come in handy for wiring repairs to tow vehicles and trailers, under the vehicles in a hostile environment.
I was going off of what someone said in my previous thread, about my CCRM failure quoting from this thread
http://www.stangnet.com/mustang-forums/threads/fan-spins-intermittently.862237/
You'll need at least a 40 amp relay to operate the stock fan. That 30 amp setup in your link will eventually melt down. The 40 amp relay that we already have is really too small for this application, but it does last 15 years on average so I'd say it's ok.
So I went with what he said. If you do go this route, I would shoot for a 50 amp, I went 45 because I didn't see a 50 and it was good enough for me.
(and that 30amp relay he's referring to was the initial fan controller I was considering buying till he said something).
Darn it... Sorry for yet another post, but I meant to ask you, what was wrong with the wiring in your car?
I am having a fan failure issue right now, and it turns out that what I thought was the CCRM, is not, and I have not tracked down any "bad" wires yet. It is starting to look like a deeper failure, possibly the ECM. If yours is just wires, what made you elect to not just repair wires? Not knocking what you are doing at all, just curious as to the thought process. You may have thought of something that will help me get my fan going again.
You should go over my thread page to page, if you're sure it isn't the CCRM, run jumpers to the fan and test it. If the fan spins then I would then test the temperature probe located on the passenger side front of the lower manifold. If that works out too, then you could be me and come up with bad wires. I decided it was the wires being compromised because I was getting 12v at the fan on high speed and low speed (whichever was meant to be on) and I tested the ground by grounding the wire. I just decided it would be easier to say that the fan isn't getting enough amps through the poor old wires and it wasn't spinning the fan. I also tested a ford tarus fan that was smaller and it didn't spin, but spun with jumpers.
I went through some extensive testing (extensive as in a lot of different tests, multiple times) and called it fubar.
I couldn't tell you if it's the ECM or not though.
And finally I chose this route rather than repairing the old harness because I wasn't certain which wires were bad, the ground going from the CCRM to the fan, or the 12v or all or what. I then decided I rather shell out the 100 dollars for a clean aftermarket option and tuck the rest with zip ties.
So ultimately, just go over that thread, and it 'should' lead you to your answer. It was recommended to either go aftermarket for better security, or the possibility of going stock again with a new(used) stock harness which is a lot of work.
I the difference between our two cases is that I had 12volts at the fan, and you don't. So I had power, just not strong enough I guess
You could use a fuse in the underhood box that's also switched (something like the 25 amp ignition/audio fuse looks promising). Here's your 
