Kill switch for my 2008 VW
 

Ok, I've found a fuse that, when I pull it, causes the engine to stall but does not trigger the Check Engine Light. I probably ought to pull codes to see if it throws a code but doesn't light up. Anyway, it's a 20 amp fuse under the hood, and I don't want to cut the wires going to it.

Any suggestions how to interrupt it with a momentary button? I'm imagining a normally-closed relay, an inline fuse holder, and tabs going in to the original fuse location, but maybe there's a more graceful solution.

What style fuse are we talking here? And why is cutting the wires a no-no? Just curious.

Oh yeah, what's the goal for the kill switch? Security?

Standard blade fuse (not mini). I want a lease-friendly easily reversible mod, so cutting such an important wire is not my first choice.

The kill switch is for EOC. I should have mentioned that. I've been just keying off, but it's sub-optimal for a few reasons. One is that keying off is annoying, particularly so with the VW's weird key. Another is that the gauges go dead while the key is off, but I have to keep it off for what feels like forever for the engine to stop or else it will re-fire. The newest reason is that the ScanGauge doesn't get data while the key is off, and accuracy is suffering as a result.

I don't know for sure that working the fuse I found will fix those problems, but I can't test until I wire it up, and once I do the same configuration should work for any other fuse too.

20A is a little large to run directly through a switch on the dash, but it's certainly possible if you don't want to bother with a relay.

How do you plan to mount the switch if modifications are taboo? I guess you could leave it hanging or is sticky tape or something acceptable?

Actually, the fact that you said momentary should've clued me in. Momentary's not much use for a security switch. :)

I'm not sure how or where I'll mount it. There are tricks for lease-friendly mods like mounting stuff. I could use adhesive/tape, zip ties, or maybe something else depending on what kind of switch I use.

I mounted an extra 12v outlet in a spare button space, and saved the blank to put back in that space before returning the car...
https://lh5.ggpht.com/_oNsRR_T1Qx0/SA...0/IMG_0618.JPG

I could probably open another blank and make a mount, or I could buy a button that fits those blanks, like a spare traction control button. Still, I think I'd rather have it on the gearshift, so maybe hot glue and/or zip ties.

Because of my 10 year/100,000 miles warranty (for me, that means 10 years) I have to worry about a certain degree of modification, but fortunately switches are OK!

So once you kill the engine, you'd need to restart with the keyswitch, right?

No, I bump start. Another user, PaleMelanesian, has refined the procedure into a few very easy steps, which I will attempt to reproduce here:
1. Shift into a higher gear than you'd drive at that speed (for me, there's no such thing, since I'm good for 25 in 5th)
2. In one quick movement, let the clutch partially up and immediately back down -- just enough to make a slight amount of friction and kick the engine over, not as much clutch wear as you might get pulling away from a stop
3. Wait for engine to catch and smooth out (once it starts to fire I lay on the gas for my rev-match)
4. choose gear, rev-match, go

For me in my car, it all happens within maybe two seconds. 5th gear, pulse the clutch, lay on the gas, clutch up, and I'm powered again.

Well no wonder you don't want to mess with the keyswitch. Do you lose power steering with your engine off?

No, my car has electric power steering. It's a little 3000 pound hatchback and would probably be fine with manual steering anyway.