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Discussion Starter #1
I'm in the midst of installing a set of heated grips on the bike (Germany's cold, and I like to keep my riding season year round). I'm trying to figure out which headlight wire is hot, and for this I have my old craftsman multimeter. I have, however, completely forgotten how to use the bloody thing over the last 2 years of inactivity. I understand that red is positive, black is negative, but as for the actual settings to determine if power is flowing through a circuit, and how much resistance is in a circuit, I'm lost.

Can anyone help me out?
 

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Set your multimeter to the DCV setting at anything over 20VDC. The DC position usually has two parrallel lines one over the other, one broken and one solid. If you put your black lead to any ground, preferably right on the battery and probe with your positive lead you'll read battery voltage when you hit a live wire.
If you're measuring resistance, ohms, you measure across the device in question in an unpowered circuit. I.E. for a light bulb you place one lead on the brass shell and one on the lead post on the bottom. to get an accurate reading make sure your hand is not touching both leads at the same time.
To measure amps you have to use a series circuit, The multimeter is set in the amps position and is placed is series with the load, I.E. you create a 'circle' with the battery, multimeter and load. Do not leave the multimeter connect for a long time, most have a limit as to how long them can conduct without overheating.
You aren't powering the grips thru the headlight wiring are you, hopefully you're using a relay. If not you're asking for trouble as the starter switch is almost maxed out stock.....Mike
 

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I'm in a hurry, so I can't take much time.

NOTICE: MAKE ABSOLUTELY SURE THERE ISN"T ANY VOLTAGE in the circuit if you are measuring RESISTANCE (OHMS).... if there is, you may ruin your meter. Check this by using the voltage feature as stated above. Gotta get to the ski slope for a race.
 

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As an old retired electronic tech, and ham radio op, I'd like to tell you it would be in your best interest to not try to measure amps or current. As a previous poster mentioned, the meter has to be inserted in series with the circuit. Most cheaper meters will not even handle the amperage or current in a light bulb. They will only measure milliamps. So stay away from anything that says current, amps or milliamps on your meter. You can get into some trouble if your not familiar with using a meter set to current/amps/milliamps. However, voltage measurments and resistance are relatively easy. There will be a different plug for your test leads to plug into at the meter indicating something like current, milliamps, amps. Don't use these. Plug your leads into the volts/ohm, red to positive, black to negative or common. Set your meter to 20 volts as mentioned, 30, 40 or 50+ volts would also be fine depending on your meter. This is what you will use to check if voltage is present. Connect the black lead to the black wire which is negative. Connect the red lead to the red wire which is positive. Check if voltage is present. If it is not, move the black lead and touch it to the chassis, if voltage is present now, then you have a bad black or negative wire. Black or negative wires always make it back to the frame somehow. So if you don't have voltage at the black wire, but you do when you move the lead to ground or chassis, it means the black wire did not make it back to ground, and the black wire is bad. Make sure the positive or red never touches the chassis or any other metal connected to the chassis or sparks will fly. If you are missing the needed voltage, usually you would troubleshoot with the meter set to resistance or ohms. 0 ohms is a short which would indicate a good wire measured end to end. But This is when I would disconnect the positive (red) wire connected to the battery. Like the previous poster mentioned, voltage and resistance don't mix on a meter, and to troubleshoot a broken wire you will probably use the resistance setting on your meter. Change your meter to ohms or resistance. Probably a low setting like 2000 ohms, (2k) normally the leads or the wires plugged into your meter won't have to be moved. (There is usually a different plug for current (amps) again advising to not use this) Now you can check any wire from end to end for resistance. 0 ohms, or close to 0 ohms, indicates a good wire. Make sure your meter is working correctly though by touching the two lead tips together. The meter should read close to 0 when they are touching and infinity when they are apart. Things can get confusing though, sometimes there are devices that insert resistance into a circuit making it look bad. I don't know your knowledge of electricity so I hope I haven't insulted you by being too basic. I assumed you had a cheeper older meter. The newer meters, or more expensive meters, are often more automatic and self protecting. Feel free to question further. Hope that helps. The other posts are good also, but I felt strongly to warn you about trying to measure current in a circuit. Usually this is for experienced techs.

Bocco
 

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Get a battery (AA, AAA, 9V, etc) and make sure you are measuring properly before putting the leads int eh bike. If you reverse the red and black, no damage will be done, but the reading will be negative. As stated, stay away from trying to measure current.
 

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Discussion Starter #6
Don't particularly need to measure current, just presence of power, since I know that what goes to the headlight is sufficient to run the heating elements. And the measuring resistance thing is more of a curiosity issue, which I'll probably never bother with.

The meter in question is a craftsman, roughly $60 or so when I bought it, so I figure it's not too bad.

As to the starter power overload issue, on this bike it shouldn't be a problem (ZZR-600), and these inserts don't pull much power anyway. Normally I'd run a relay and just wire from the battery, but I have yet to find an electronic supply store in this country, and the ammenities of that nature on base leave much to be desired.

Thanks for the advice, everyone. I'll probably get this finished tomorrow.
 

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Discussion Starter #7
Done. Everything works nicely, the load on the headlight circuit is very small, so no problems with even a tiny amount of dimming, and since I wired into those, don't have to worry about the battery.

Thanks for the help!
 
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