How do you use a Multimeter?

CiscoPath · 03-02-2009, 09:21 PM

I just purchased one of these at Home Depot for some wire work i'm about to start in the car.

Never used one before in my life and the instructions it came with are too long and drawn out to hold my attention. Guy at the store told me if I want to read 12V, set it on 20k. I have to six volt batteries here. Using it on one gave a reading of -5.12. When I went for a full 12 volts, it only gave me -1. Am I doing something wrong? Are the numbers supposed to read negative (-) ?

clutch1 · 03-02-2009, 09:52 PM

Yes, you are doing it wrong, lol. 20k is a reading of resistance (up to 20k ohms, specifically), which means that no other voltage can be flowing in the circuit (ie test subwoofer coils, wires for continuity, etc). If you ever test for resistance and get a negative number, that means there's power in the circuit somewhere.

To measure a car battery set it to the black 20 (that's 20v DC), and then test between the + post and ground (- post or chassis). The numbers may read 12.6 or -12.6, depending on if you're touching the positive lead to the positive post, or vice versa, just something to remember.

The red numbers are for VAC, of course.
The little sonic looking thing is the tone setting.. basically it'll emit a tone if you measure a wire and it had continuity.. useful for fiding broken wires/ bad ocnnectors/etc.

CactusWill · 03-02-2009, 10:13 PM

The numbers are supposed to read negative on direct current if you have the polarity reversed. Alternating current polarity doesn't matter (not for the voltmeter at least)

Ryan from Ohio · 03-03-2009, 06:34 AM

Left side is Ohms. You need your common wire (black) in the center. The red wire in the Ohms. Then you can check for Ohms. When checking Ohms the item your checking must be pulled out of the circuit otherwise you are testing the entire circuit.

Other side is volts. Must move the red wire also.

The number shown on the meter is the maximum for that selection. So if you have something that should be 18Volts start at 20. Etc, etc.

CiscoPath · 03-03-2009, 07:14 AM

Thanx for the info, guys. Gonna do some testing when I get off work. Only have a week to get this remote starter installed.

Gr1m · 03-03-2009, 08:58 AM

why do you need a multi meter for a remote start?

cherrington17 · 03-03-2009, 09:10 AM

testing ohm for ignition?

clutch1 · 03-03-2009, 12:34 PM

Quote:

Originally Posted by Gr1m

why do you need a multi meter for a remote start?

Uhm... testing the ignition wires so you tap into the right ones for each remote start wire? You don't just tap them based on color, that's foolish and asking for trouble.