stuck my voltmeter where it wasn't welcome

[particlewave]

A test light would be much worse! Much, much worse! Electrons allowed to flow through a conductor freely is not a good idea.

What you need to do is use a diode so that current only flows through the meter and into ground...but I'm not going to elaborate because if you didn't know that already, you shouldn't be poking around with a mm.

[stephen wilson]

What type of MM were you using? A quality meter should have very high input impedence in Voltage mode, and not couduct any measurable current.

[JFP in PA]

Originally Posted by particlewave

A test light would be much worse! Much, much worse! Electrons allowed to flow through a conductor freely is not a good idea.

What you need to do is use a diode so that current only flows through the meter and into ground...

Which is exactly what a test light would be doing............. The problem with using a meter is most people bridge across two terminals or wires, not to ground. To be totally safe, a low range clamp meter would be even better, but most do not own one.

[Meir]

Originally Posted by JFP in PA

Which is exactly what a test light would be doing............. The problem with using a meter is most people bridge across two terminals or wires, not to ground. To be totally safe, a low range clamp meter would be even better, but most do not own one.

+1
most of today's test lamps, are protected by an electronic circuit.
unlike the old school lamp that was made out of ... lamp, the new ones has LED's and/or buzzers seating on a protected circuit.
i use this one for basic stuff:
SST 42-Volt Test Light-SST42V at The Home Depot
and this for more advance:
Power Probe 3 Demo Video - YouTube

both are not cheap, but if you want to be safe, you need one of them or similar.
needless to say, i'm not affiliated with one or the other ( although i wish i was )

[Meir]

that's funny.
as soon as i posted my last post, i received an email from one of my techs.
this is the starter wire for the 2013 panamera.
going to the data base.



wire is cut. no CEL no problems.

[tranceatlantic]

Thanks for all the help guys. I try to be careful and I was using a meter because I know they don't draw current from the wire you are testing. For that reason I also didnt think a lamp would have been better but an LED version would draw very little current. I had the ground side of the meter held at a ground point so I really dont know what happened. Thats where the Guinness comes in.

To answer some of the questions........

I have a cheap little digital meter from radio shack - nothing fancy

The motor is not currently supercharged but thats the direction Im heading. Im trying to get the controls and extra diagnostic stuff in place first. I realise Im going to have to look at how much current each component needs. Sounds like a wire from the DME bus is the easy solution (Meir suggested black/brown at pin 56) but pulling too much current from the is scary.

[Meir]

Originally Posted by tranceatlantic

Thanks for all the help guys. I try to be careful and I was using a meter because I know they don't draw current from the wire you are testing. For that reason I also didnt think a lamp would have been better but an LED version would draw very little current. I had the ground side of the meter held at a ground point so I really dont know what happened. Thats where the Guinness comes in.

To answer some of the questions........

I have a cheap little digital meter from radio shack - nothing fancy

The motor is not currently supercharged but thats the direction Im heading. Im trying to get the controls and extra diagnostic stuff in place first. I realise Im going to have to look at how much current each component needs. Sounds like a wire from the DME bus is the easy solution (Meir suggested black/brown at pin 56) but pulling too much current from the is scary.

the wire i suggested is basically the 15 feed to the ECU (AKA true ignition ).
the information was taken from the circuit diagram in the Bentley book (highly recommended if you have any intentions working on your car yourself)
this wire also feed power to other element in the car except the ECU (as mentioned in previous post).
adding a relay will drop the load on that wire, and will allow you to use a separate fuse for your setup.
select the correct fuse based on the current drew.

[jsceash]

X59 Plug pin location 4 White plug next to ECU (left of ECU) Red wire blue stripe fairly heavy wire come from ignition relay and turns off about 30 seconds after ignition is off. Does not come from ECU so can't hurt ECU. It turns on a half dozen other relays. I'm using it to turn on power to my Accusump solenoid ( .6 Amp) for over a year with no ill effect. I installed a 1 Amp fuse link after the connection. It come from fuse block C fuse 1, 25AMP fuse supplied from 80 Amp fuse at distribution block near battery.