Testing the alternator on your 1.3L Suzuki Swift (Chevy Metro) is one of the easiest diagnostic procedures that you can do on your car.
The tests that I'm gonna' show you in this tutorial will help you to accurately diagnose a bad alternator using a multimeter.
Contents of this tutorial:
Symptoms Of A Bad Alternator
Cranking your Suzuki's engine (to get it started) draws a lot of battery ‘juice’ and it's the alternator's job to replenish the battery once the engine has started and is running.
Your Suzuki's alternator is also tasked with providing the electrical current required to run the: fuel pump, ignition coils, A/C compressor, radio, blower motor, headlights, etc., as you're driving down the road.
When your Suzuki's alternator fails, you'll notice one or more of the following bad alternator symptoms:
- The charge light (also known as the battery light) will be shining nice and bright on your Suzuki's instrument cluster.
- Whenever you turn on the headlights (night driving), they glow very dim.
- The engine won't crank. It will only crank and start if you jump start your Suzuki.
- The only way your Suzuki cranks and starts is if you charge the battery.
- Your Suzuki stalls and won't crank (unless you jump-start it).
With this info under our belts, let's get our first test under-way.
TEST 1: Battery Voltage Test With Engine Running
To get this show on the road, we're first gonna' see what the battery's voltage is with the engine running.
If the alternator is doing what it should, the battery's voltage (with the engine running) should be between 13.5 to 14.5 Volts DC.
If the alternator is fried, the voltage will be around 12.5 Volts (or less). The longer the engine runs, the lower this battery voltage will become (till the engine stalls).
NOTE: You'll need to make sure that the battery has enough of a charge to keep your Suzuki Swift (Chevy Metro) running for at least 5 minutes to do this test. If the battery is completely dead, charge it up enough so that it can crank and start the engine.
These are the test steps:
Crank and start your car and select Volts DC mode on your multimeter.
Probe the positive battery terminal with the red multimeter test lead.
With the black multimeter test lead, probe the negative battery terminal on your Suzuki's battery.
Your multimeter is gonna' register one of two possible readings and they are:
1.) A steady 13.5 to 14.5 Volts DC.
2.) Or 12.5 Volts that will decrease the longer the engine stays running.
Put an electrical load on the alternator to further confirm that it's either charging or not charging.
You can do this by turning on every accessory possible (inside the vehicle). For example: Turn on the A/C or heater on high, turn on the windshield wipers, turn on the headlights, turn on everything and anything that uses electricity inside and outside of the vehicle.
Your multimeter will show you one of two things (as you turn on all of this stuff):
1.) The multimeter will register a nice and steady 13.5 to 14.5 Volts DC no matter what gets turned on.
2.) It will register 12.5 V DC and this voltage will decrease more and more as you turn on stuff inside your Suzuki (Chevy) vehicle.
OK, let's interpret your multimeter test results:
CASE 1: Battery voltage with the engine running was 13.5 to 14.5 Volts. This voltage test result tells you that the alternator is working (charging the battery).
No further testing is required, since this multimeter test result eliminates the alternator on your Suzuki Swift (Chevy Metro) as bad.
Now, if you're having to jump-start your Swift (Metro) to get it going, this test result points to a bad battery or a parasitic drain. A parasitic drain is tech-speak for something staying on (usually inside the vehicle, for example: a dome-light) and draining the battery while the engine is off.
CASE 2: Battery voltage with the engine running steadily dropped down to 9-10 Volts. This is a clear indication that your car's alternator IS NOT charging the battery.
Replacing the alternator at this point usually solves around 90% of the No Charge conditions. That's right, you could stop testing here and say: ‘The alternator is fried' and be done but..
I suggest two more easy tests to be absolutely sure it is bad. For the first test of the two, go to: TEST 2: Checking The Continuity Of The Bat (+) Cable.