Basic Automotive Electrical Troubleshooting 1
Check your battery's standing voltage by clipping the good lead of a multimeter to the positive battery terminal. The cable ends must be absolutely free of corrosion for this test. Clean them using a wire brush. Clip the multimeter negative lead to the negative battery terminal.2Set the dial for volts. You ought to read no less than 12.6 volts. If it reads less ">Auto diagnostic tools, you will need to charge the battery and take another reading.If the battery remains below 12.6 volts, or features a reduction of over two volts, you will need to verify the cells.3Remove the sealed or pop-out battery cell caps and check each cell having a battery hydrometer. The cork or plastic floats within the hydrometer really should float inside the "Green" section, with no cell appearing in the "Yellow" or "Red" margins.
Yellow or red readings indicate a defective cell, which means the battery has to be replaced.4Check the charging method by putting the good lead of a multimeter towards the good terminal of the battery. Spot the multimeter unfavorable lead on the negative battery terminal. Start off the engine and read the charging method voltage output. The charging technique voltage should read between 1.five and two.0 volts more than the battery standing voltage, or 14.1 to 14.6 volts. If it doesn't, a problem lies together with the alternator, alternator belt or regulator.5Turn the engine off. Connect a clip-on amp meter for the positive starter cable. Set the amp meter for the 1,000 amp scale. Disconnect the ignition coil wire from the coil or coil pack. Ground the coil wire towards the engine block using a piece of coat hanger wire. Have assistant apply the emergency brake and place his foot on the brake pedal.
Have him try to start off the car in neutral and let the engine crank for several seconds.6Look at the starter amperage draw reading on the amp meter . Refer to your owner's manual for the maximum quantity of amperage draw allowed for the vehicle. Something over 200 amps are going to be suspect, indicating resistance within the starter winding. Check your external solenoid by placing a jumper wire onto the starter battery terminal on the solenoid plus the other end of the wire onto the hot sender wire. If the solenoid does not engage to spin the starter, the solenoid contacts have failed.7Check your lighting components by 1st removing the lens caps using a screwdriver and examining the bulbs. Replace any bulbs which have broken carbon filaments. Check the socket connection for corrosion as well as the bulb socket ground wire. Headlights, turn signals, brake lights, plate and backup lights may be checked in this style.
In the event the bulbs show superior filaments, visit your main fuse box panel and examine the suitable fuse for every single lighting component.8Look at the filaments in the spade or tube-type fuses. Replace any that appear burned or disconnected. Examine the principle headlight relay if both headlights fail to operate. Switch the suspect relay with a further identified superior relay and see if they work. If they work, replace the negative relay using a new relay. When the fuses, relays and bulbs appear very good but no illumination results, run a jumper wire from the good terminal on the battery for the hot lead inside the bulb socket.9Turn the ignition crucial towards the "On" position and make certain the bulb socket features a great ground connection. In the event the bulb lights together with the jumper wire, it indicates a defective wire from the energy source. Use a 12-volt test light to probe a suspect wire from its component supply to its nearest connection to a battery energy supply.
10Stab the wire using the sharpened test light probe and watch for the test light to illuminate. If it fails to light, the wire will not have voltage to it at that point. Look for any in-line fuse or fusible hyperlink additional upstream toward the power supply, and replace any that appears blown.11Disconnect the battery supply or fuse to a element once you must check the ohm resistance within a wire. Set a multimeter for the low ohm setting. Location the ohmmeter leads at opposite ends in the wire or on the opposing sides of a switch. Read the ohms. If you have a greater than standard ohms reading, it indicates resistance in the wire or switch or maybe a corroded and partial ground. Clean all ground wires and straps ">Auto tools, in particular braided engine ground straps.12Refer for your owner's repair manual for the normal resistance allowed for the wire or switch in your car. Remember that the gauge (diameter) of wire when thinking about the maximum allowable ohms. Your owner's repair manual will possess the wire gauge sizes and element voltage specifications, along with the amp and ohm threshold limits.
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