Hey guys so i lost my manual and my searches netted me different results so maybe you can help. I am doing an alarm install and i need to make sure everything is correct so im trying to check all of which wires are positive and which are negative. I have a multimeter but all i have ever used it for is checking voltage. How do i use the multimeter to check and find out what wires are positive and what are negative? Thanks

 

You didn't need 2 posts to find that out, you know voltage, for ground use the continuity setting on the meter, should be between ohms and diode test setting, it's the one that if you hold the probes together the meter will beeeeep. 94

 

Your doors, door locks, and trunk are negative trigger. Your parking lights are positive trigger.

 

set meter to DC Voltage ...ground black lead and probe w/ red lead

 

If your multimeter leads are long enough you could hook one lead to the battery and probe with the other when testing voltage. You could also do the same with a test light IF YOU KNOW that your wires are not connected to sensitive electronics. Play around with the meter at your battery. With the Fluke meter that I use at work hooking up backwards will give a reading in negative units when measuring Volts.

Your wires don't know postive or negative. Though there is a significance to polarity and direction of current flow.

Thing to do is hook to ground with your meter's ground connection (black wire). Then probe with the red "hot" lead. All hot wires will show a current if you properly make a connection.

Next hook up to battery hot ("+") terminal with your meter red lead ( power ). Probe with your black "ground" lead. Any proper ground wire should register a Voltage reading.

If your meter is not auto ranging you will need to be carefull of units.

If you are adding on an aftermarket, proprietary kit a phone call to the manufacturer might yield some help. A good company wants you to have a good result with their product. If you tell them you lost your directions / electrical schematics they might be willing to fax a new set to you.

Another thought would be to contact a reputable installer to do the job for you.

Are you using proper crimp connectors or soldering? Or were you planning to twist the wires together, Or some other unhappiness? Mechanically sound connections yield reliability and good times.

When in doubt as to a good ground connection use the battery ground post.

Best of Luck!