grandpawmoses

Theta,
Please see my attached .jpg scan of my thoughts on using the "add a circuit" for your solderless idea.
You would not need to fabricate the "double" jumper piece. Simply put the original 20 amp NPP fuse in the top slots of the "add a circuit" and plug your single plug lead into the bottom, right side slot of the "add a circuit".
What do you think. I have not purchased an "add a circuit" so I have not verified its' internal wiring.

Theta

The AGC I used inside at the switch isn't an AutoZone part, so I ripped it out to re-do it with the new hardware.

I understand what you mean, though - I placed the AGC (or ATM - I will give the choice based on preference) right before the switch for the ease of diagnosis. You're suggesting putting the fuse on the +12v hot from the box before it enters the cabin (and preferably inside the box). This is a very good idea, and as I've not put the fuse info up yet, I believe I will do this for the sake of safety.

Reading your other post now - good stuff.
.

Theta

Your thinking is spot-on. By not having the fuse in the cabin, we can do what you propose and save time and money on wiring in the additional AGC/ATC/ATM fuse.

Theta

Now that I've found an additional two sources for the Micro2 Add-A-Fuse, I may eliminate the solder method - it requires more work, tools, and time. In addition, since the fuse will now be located within the box, it actually becomes a bigger pain-in-the-butt than the Add-A-Fuse.

Anyone have thoughts on this? Everyone always wanted soldered connections, but now with Micro2 tap options out there, that route sure looks a lot better...

grandpawmoses

That's what I think too. No soldering, no need to buy a fuse to destroy, less construction, and it would be quick to return to original configuration if needed.
I like the lighted switch and the location you chose for it. Looking forward to your final tutorial.

Theta

Agreed. I will post the alternate (Amazon and eBay) links, and add some other appropriate switches available, as well.

AutoZone is just rolling out the Bussmann Micro Add-A-Circuits (not in all stores yet), so it's easier to pick either one or 3 up from Amazon with Prime shipping.

I got caught up in having the switch inside (my gauge fuses are AGC, but a pain to get to), and forgot how easily the existing 20A would be to use. Thanks for taking the time to draw that up - it's always easier for us to draw than it is to write out an explanation... Well, unless it's an equation - though I still normally take a photo of my scribbles, as well.

This has to be the weirdest tutorial for people watching, in that it's changed so much. Thought about bringing it down and re-tooling, but input like this is very much welcome and appreciated.

grandpawmoses

This might be one more concern. The "tap a fuse" I looked at only had a 10 amp rating.
I get paranoid about putting a 20 amp fuse in a 10 amp rated "tap a fuse".

Theta

Yep, noted that before even buying it. Engineer in me said "wait, melted wiring".

Checked with Bussmann, and then looked at the other taps online. 25A is the actual maximum. The lead attached is a 16AWG, and 16AWG is rated for 20A at up to 10 feet in 12V circuits (25A @ 6ft). Past that, it drops to 15A at 16ft, etc. We'll be using 6-7 feet of wire after the cutting (starting out with 10, and trimming way down), so we're well within the guidelines of safety.

Since they didn't use 14ga, this was a liability limiter. Additional fun fact is that the 2A designation is silly, since a 1A is perfectly fine.

And even more odd is that GM used a 20A fuse on the valves, as the measured current is around 4A during actuation. Sometimes engineering teams baffle me.

Theta

Funny enough, I just saw that this (nearly exact) mod was done on the C6 8 years ago. Nothing new here, just a different set of part numbers and a new section for everyone.

More pictures, though.

grandpawmoses

My guess is that while the motors pull 4 amps, they probably have an 8 to 10 amp start up surge. Add some extra so it's not accidentally blown & ya need a 20 amp fuse.
In all reality the 10 amp "tap a fuse" will probably be okay but now I've played the paranoia card. Will a 20 or 25 amp rated "tap a fuse" fit under the closed fuse box lid?

Theta

You're right - it's for the inrush current. They could still limit it, but it's one of those 'who cares' items since it's external and a simple circuit.

A 20-Amp rated tap is identical to this one - just a branding and spec difference. To give you an idea of marketing on the Add-a-Fuse, here's the exact setup on Amazon with a 20A rating:


Note that it uses the same 16ga 5" lead. The cheaper Chinese clones are rated at 30A, but I'm guessing that's just because they saw that you can shove a 30A in the socket. Don't mix 30A with 16ga wire, folks.

We're good on terminal material (it's not thin like a maimed circuit would be), and the lengths noted before assume a 20% margin of error. You can actually use 18ga with 20A for up to 5ft runs, but I personally wouldn't.

Here's an AWG chart summary @ 12 Volts:

grandpawmoses

I believe you have a winner.

Theta

Always good to have another pair of eyes on things like that - nobody wants a wiring fault that leads to a nasty fire.

xp800

Awesome work as always Theta!

If you are able to find out, can you add the part number for the trim piece drilled for the switch? I will eventually do this and I always like buying replacement OEM parts for the ones I modify.

meyerweb

Looking / sounding good so far.

I hate crimp connectors, though, so I'll either solder them or use Posi-Locks where butt connectors are needed. Posi-Locks inside the fuse box will also make it really easy to disconnect everything in the fuse box and set back to stock before a trip to the dealer.

Thanks. Look forward to seeing the rest.

Theta

Totally understand - I'm a solder guy, myself.

FYREANT

so.... would we be able to use this to actuate the NPP valves on a non NPP car that added NPP mufflers with actuators after the fact?

Theta

In typical fashion, there are four part numbers for this one piece in the EPC. Two are for the right hand side, and two for the left. Of the two on the left, one is cheap, and one is expensive. Both show the same position, etc... I'll work on figuring it out for you.

Theta

This would only be for factory-NPP cars. If the NPP conversions end up getting figured out with regard to the PWM and CCM, then you could do something similar.

I'm not sure if the non-NPP cars have Fuse 41/42 actually leading anywhere, assuming it has a pinned slot in the first place.

I tried to figure that one out a while ago, but it will come down to a PWM converter and a switched relay to bypass the CCM - pretty positive of that.

FYREANT

well crap. I was hoping that you had that figured out too as part of your DIY. oh wells..