In the next few days, I'll need to tap the - wire to the high beams, the + wire to the parking lights, and the VSS wire coming from the ECU. While in theory, I could strip the insulation off mid-wire with a knife and solder in a splice for a new wire, I rate the likelyhood of me pulling that off without cutting the existing wire in half as 0. So I'm looking for a strong, reliable, long lasting, safe way to tap existing wiring WITHOUT risking screwing up the existing wiring.

How do I do it?

BTW, is there really no FAQ for stuff like this?

I believe Posi-Tap is better than blade types, because it won't cut the strands. If your taps are for sensing the voltage and not for powering something up, which should be the case here, except maybe for the high-beam wire, then mechanical taps are OK. If the circuit being added will draw a significant current (say, 5A or more), a solder splice is still the way to do it. Before using the knife, use a wire stripper to cut through the insulation.

Doesn't the Posi-Tap system require the existing wire be cut in half before you can make the splice? Honestly, from the horrid description of the product, I couldn't figure out how it was supposed to work.

The high beam and parking light tap are to trigger relays for Hella Rallye series lighting. The VSS tap is to feed a rally computer.

Posi-Tap is the name for their T-tap and the original wire doesn't have to be cut when using it. There may be some room for confusion between Posi-Tap and earlier Posi-Lock, which does require cutting.

The only ways I'd ever tap a wire are, in this order:

Solder (cut wire, put in heat shrink, splice back together)
Solder (strip without cutting), taped up
Quick Disconnects (cut the wire, put a male on one end, a female on the other. Use another male and another female to create a pass-through type connection)
Butt Splice (cut, strip, crimp)

OK, I found a page showing how the Posi-Tap Connectors work (http://www.webbikeworld.com/r2/posi-tap/posi-tap.htm). Frankly, that's bloody brilliant because you can take it off later without damaging the connection.

So I guess it comes down to using Posi-Taps or cutting and soldering....

Just three days ago, I had to repair a worn wiring harness where it passes from the body into the tailgate on a wagon, and it did require soldering (in a tight spot, in inconvenient position), but for the task at hand, I believe Posi-Tap will do the job. Then again, if you consider the rally computer a mission-critical application (and then the fog lights also I guess), you might want to use soldering after all.

Just three days ago, I had to repair a worn wiring harness where it passes from the body into the tailgate on a wagon, and it did require soldering (in a tight spot, in inconvenient position), but for the task at hand, I believe Posi-Tap will do the job. Then again, if you consider the rally computer a mission-critical application (and then the fog lights also I guess), you might want to use soldering after all.

Meh. It's not for money, and if the lights go out, I just slow down. Not to mention if I'm actually on-course, I can always hot wire the lights on. My real consideration for this is not having to redo it once a year, not having the tap outlast the car.

I too am considering tapping the high beams to power a relay for a set of driving lights..... My plan is a bit more expensive but fully reversable (and does not require holes in my wires)..

I'm just going to buy a few male / female headlight bulb connectors and make my own harness.. Advantage of this is that I can setup a relay in the system to give my high beams full 14.4V AND allow me to tap at will without touching the factory wires.......

I too am considering tapping the high beams to power a relay for a set of driving lights..... My plan is a bit more expensive but fully reversable (and does not require holes in my wires)..

I'm just going to buy a few male / female headlight bulb connectors and make my own harness.. Advantage of this is that I can setup a relay in the system to give my high beams full 14.4V AND allow me to tap at will without touching the factory wires.......

That would be the ultimate way to go.