Have a 2000 Chevy tahoe. The voltage indicator goes from 14 to 9 off and on. I had the alt and battery checked and they checked good. It may not doe it for a week orso, then does it again.

SOURCE: alternator not charging

Check for voltage with a multi meter or volt guage most of the GM trigger wires come from the computer and are only 5 volts. 5 volts is not enough to light some test lights. If still nothing the problem is probably the computer. But it can be manually excited. The two terminals in the alternator on the left of the pigtail (when looking from the front of the van) need + power. the far left is the trigger wire the one next to it is ignition power.

SOURCE: no power to starter 2004 chevy tahoe

Hi
It could be your neutral safety switch. It could be the starter relay which is located in the fuse panel box. It could be the smaller wire going to the starter could be loose or corroded.

SOURCE: 2000 ford zx2, battery light keeps coming on/off,

There seems to be a no charge state in this case. i recommend checking the charging system. use the procedure below to isolate this issue.

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.)))

SOURCE: 2000 chevy silverado 1500 battery light keeps

When was the alternator replaced? was it a remanufactured alternator? This is common on GM trucks, fluctuating voltage is caused by a faulty alternator voltage regulator. Have the alternator tested, strong possiblityits defective!!Hopefully this helps!!

SOURCE: 2002 chevy tahoe ,vehicle has factory alarm with

If possible try tapping on the starter with a hammer while someone is cranking it over. The electrical system test only tests for amperage draw and not dead spots. Do this after checking battery connections if connections do not correct the issue. If it cranks while tapping the starter then starter is having a issue.