TOOLS NEEDED:
1. Digital Multimeter with Audible Restistance / OHMS, Direct Current
Note: This is just a beginners guide for people who have no experience in measuring current or resistance.
Resistance
Okay, so your trying to figure out why your electrical functions aren't working properly on your car. You start buying new parts, replacing things that the wiring connects to, and your electrical functions still arent working.
I know everyone has gone through this at least one time in their life. Its frustrating, and doesn't make life nice
Well, instead of spending money on parts that could or could not fix the problem why not check the electrical side of the problem (wiring, fuses, resistance).
First you have to know how to use your multimeter. One that you need to know are OHMS. The ohm (symbol: Ω) is the SI unit of electrical impedance or, in the direct current case, electrical resistance. On your multimeter, there should be a setting with the Ω picture listed. this is OHMS.
An ohmmeter can be used to directly measure an unknown resistance R.
This is the simplest way to measure resistance. It is important to realize
that an ohmmeter can not be used when the resistance is connected in a circuit and a current is flowing through it!
Most Ohm meters read the following settings : 200, 2K, 200K, 2M, 20M
# In Words In Ohms ( Ω )
200 two hundred ohm 0-200
2K two kilohm 0-2000
two thousand ohms
200K twenty kilohm 0-20,000
twenty thousand ohms
2M two megohm 0-2,000,000
two million ohms
20M twenty million ohms 0-20,000,000
So your probably wondering, what setting would I set this up at to read for what im working with? If you have a repair manual it usually tells you what the resistance should be for what your working with.
Example:
You are trying to find out if your sensor is bad, so you refer to your manual. It says to test pin 1 and 3 on your sensor plug. It says in the manual specs say between 490 and 700 ohms of resistance. So you would set your dial indicator to 2K. because its higher than 200ohms and lower than 20,000. GET IT??
Continuity
Your leads (cables) from your multimeter have a point at the end. It makes it nice because you can push it inside a plug and touch the pin instead of cutting and hacking your wiring up to get a good connection.
If a circuit has a path through which electricity can flow, it is said to have continuity. A Curicuit with continuity is termed "closed"/ If current cannot flow, because of extremely high resistance or a break in the circuit its said to be "open" or to have no continuity. Testing for continuity lets you know if the curcuit is open or closed.
Connect your probes to what you want to test. For a break in the wiring, you would hook it to the wire in question and a good ground (Bolt, Steering Column, anything metal thats connected to the car). Read the meter. If the reading is low, it means you have continuity (the circuit is closed). If its reading "infinity" it means there no continuity (Circuit is open)
Why test for continuity?
Testing for continuity can help for figure out if you have blown fuses, open or shorted wires or conductors, operational switches, and circuit paths. If a fuse is blown there will be no continuity across the test points. If a switch is not functioning properly the will be no continuity regardless of switch position. A useful continuity test would be to verify that there is a good connection between wire. Let's say you've just crimped two wires together and want to find out if your connection is good. To Test this, you would touch one probe from your meter to one side of the connection and the other probe to the other side of the connection. If there is good continuity you should get a low resistance measurement (typically 0-1 ohm). If you want to see if your wire is shorted to the body, do the same steps, but instead of testing the whole wire go from one side of the wire to the body.
to Set your multimeter to the ohms / audible, turn it to the following picture
NOTE: Please dont ever cut your wiring, exposed wiring can cause shorts and exposure to elements can make the wiring corrode and cause the wiring to not be within manufactors specs and stuff might start acting weird!
~MP
95 Camry
Linear Mode
