My car battery was dead when went to start. I
HI. It is possible that the battery has reached its life span, and may need to be replaced. If this is a new battery, the charging system may be malfunctioning. Use the procedure below to inspect the entire charging assembly for faults.
Wear protective eye wear and clothing and remove all jewelry when checking your battery and charging system. Jewelry is a good conductor of electricity and is not recommended. Most batteries wear out every 3 to 5 years and need to be replaced. Always replace your battery with an equal replacement battery to assure proper operation. Automotive batteries have a +positive terminal (red), - negative terminal (black). Electricity is stored in the battery and then supplied to the vehicle when the engine is not running. While the engine is running the vehicles alternator charges the battery for future use. (Note: never disconnect the battery while the engine is running. If the battery cable is disconnected from the battery a spark can be generated which can cause the battery to explode or a major electrical malfunction to occur.)
To check a battery surface voltage, remove the positive terminal protective cover. Connect the +positive side meter lead (red) to the positive side battery terminal. Connect the - negative (black) side meter lead to the negative battery terminal. With the vehicle not running and the car sitting over night the battery voltage should be between 12.5 and 12.8 volts.(You will need to use a voltmeter for this testing procedure)
The alternator is rotated by a drive belt driven by the vehicles engine while it is running. Electrical voltage and amperage are generated to recharge the battery and supply voltage to the electrical system of the car. The alternator is held in place with mounting bolts. There is a main electrical wire on the rear of the alternator that supplies voltage to a main voltage junction box. If your alternator is not charging properly, your battery will slowly drain down from operating all the electrical systems in your car and stop the car from running.(most non charge states will be the cause of a loose belt or a low tension rate, due to a mis-adjusted alternator. make sure you have enough tension in the belt for full rotation of the alt pulley)
Next, you will need to check the alternators output with the Amp meter.
Testing the amperage output of the alternator is good for measuring the amount (not the level) of voltage the alternator can produce. This test can be tricky because if the alternator is weak it can still show it as producing amperage. Which is good, but if the voltage is low, it will still allow the battery to go dead. To check the amperage output of an alternator an amp meter is needed. Once the meter is connected start the engine. Next turn on all electrical accessories and raise the engine idle to about 1200 RPM. The alternator should output the max amperage it was designed to produce. Example: a 90 amp alternator should output about 88 amps. Note: An alternator cannot sustain maximum output for long periods of time. If the alternator is forced to operate at maximum output it will overheat and fail. An alternator is designed to operate at max amperage output only for a reasonable amount of time.
((Connect the voltage meter lead the same way you would in a battery static voltage check, Start engine (do not drive) at engine idle the voltage should be between 13.6 to 14.3 volts. If not the alternator may need replacing.)))
Now, if the charging system is ok, move on to the starter, and ignition switch. Use this procedure to inspect these additional areas.
Step 1
Check for 12 volts on the large wire attached to the top terminal on the starter relay. It should have battery voltage. If not, the battery, terminals or wire is bad.
Step 2
Check the small wire on the solenoid for power when the key is in the start position. Remove the small wire on the solenoid and have a helper hold the key in the start position. Check the wire for battery voltage. If there is voltage, the starter is bad. If there is no voltage, replace the wire.
Step 3
Check the fuse in the fuse box under the hood on the left fender well. If it is good, check the relay by pulling it out and checking for power at one terminal with the key off. If there is no power, the problem is in the fuse box between the fuse and the relay. If there is power, have the helper hold the key in the start position once again and check for power at another terminal from the ignition key. If there is power, the relay is bad. If there is no power, the starter circuit is suspect.
Step 4
Check to see if there is power to the neutral safety switch if there is no power at the relay. Use the voltmeter to check for power with the key in start. If there is power going in, check for power going out. If there is no power going in, the security system or ignition switch is suspect. If there is power going in and none coming out, the switch is bad. If there is power coming out, the problem is between the neutral switch and the relay.
Step 5
Remove the cover on the bottom of the steering column. Check the solid yellow wire for power when the key is in the start position. If there is no power, the ignition switch is bad.
