multimeter vows and electrical issues RE: full throttle switch

[treed2 at u.washington.edu (T. Reed)]

> Thank you Toby for a clearer information, I do have a question about you
> stated below. when you say fry, are you talking about the multimeter or the
> ecu?

Either or both. You will almost certainly blow the fuse in the meter,
causing it to perpetually read zero milliamps. But the fuse takes time to
blow (on the order of tens to hundreds of milliseconds) and current is
flowing during that time that could easily burn out components in the
ecu. Things like transistors, 1/4 watt resistors, etc. turn a toasty brown
when you try to send a crapload of current through them.

My knock sensor computer was fried when rain leaked in through the
windshield seal and filled up my fusebox, shorting out a bunch of
circuits. I don't think the ecus are very resilient against "operator
error" because they're designed to be hooked up to official vw test
equipment.

> if it is the multimeter, that would explain why I can never get any
> milliamps reading on anything. but I can still get a voltage.

Yes, this is exactly what happens when the fuse in your ammeter is blown.

Because of its design, the voltmeter does not need to be fused.. it has a
very high resistance so it takes hundreds of thousands of volts (in the
case of a digital meter) to get any significant current to flow through
the meter.

> May I need to check if my 7$ multimeter has a fuse inside (hell it I know I
> normally only use it for continuity testing and voltage readings :) with the
> new OTC automotive multimeter I will actually have a manual to read and
> understand how the damn thing works aside voltage readings...lol

;)

I'd bet it has a small glass fuse inside, but you might have to remove
screws to get at it. Radio Shack should have a replacement for ~$2.

HTH,

-Toby