The alternator on your 3.3L V6 equipped Chrysler mini-van can be accurately tested with just a multimeter.
In this tutorial I'll show you exactly what you need to do to find out if the alternator has gone bad (and thus has stopped charging the battery).
Contents of this tutorial:
- Symptoms Of A Bad Alternator.
- TEST 1: Battery Voltage Test With Engine Running.
- TEST 2: Checking The Continuity Of The Bat (+) Cable.
- TEST 3: Part 1 -Alternator Is New But It Still Doesn't Charge The Battery.
- TEST 3: Part 2 -Testing The Voltage Regulator Inside The PCM.
- Problems with the Alternator's Decoupler Pulley.
- Where To Buy The Alternator.
- More 3.3L Chrysler Mini-Van Test Articles.
You can find this tutorial in Spanish here: Cómo Probar El Alternador (2001-2007 3.3L Chrysler) (at: autotecnico-online.com).
Symptoms Of A Bad Alternator
In a nutshell, your mini-van's alternator has two very important jobs to do. The first is to charge the battery, as the engine runs, so that you crank and start your vehicle since cranking the engine drains the battery.
The other is to provide the electrical current for everything that requires it (examples: fuel pump, ignition coils, a/c compressor, radio, blower motor, headlights, etc.), as you're driving down the road.
So, when the alternator fails, you'll notice one or several of the following symptoms:
- The charge light (also known as the battery light) will be shining nice and bright on your mini-van's instrument cluster.
- Whenever you turn on the headlights (night driving), they glow very dim.
- The car won't crank. It will only crank and start if you jump start your mini-van.
- The only way the car cranks and starts is if you charge the battery.
- The car stalls and won't crank (unless you jump-start it).
TEST 1: Battery Voltage Test With Engine Running
The first order of business is to see what the battery's voltage is with your mini-van's engine running.
This first test will let us know if the alternator is charging the battery (or not) right off the bat.
To explain this a bit further, if the battery's voltage (with the engine running) is between 13.5 to 14.5 Volts, then you'll know that the alternator is working and charging the battery.
If the battery voltage (with the engine running) is at 12.5 Volts or below, then you'll know that the alternator is not working and thus not charging the battery.
NOTE: You'll need to make sure that the battery has enough of a charge to keep your mini-van 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 Chrysler mini-van 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 Chrysler mini-van'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 Chrysler vehicle.
OK, let's interpret your multimeter test results:
CASE 1: Your multimeter registered 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 Chrysler mini-van as bad.
Now, if you're having to jump-start the car 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 car, for example: a dome-light) and draining the battery while the engine is off.
CASE 2: Your multimeter registered a voltage that steadily dropped down to 9 Volts. This is a clear indication that your Chrysler mini-van's alternator IS NOT charging the battery.
Replacing the alternator at this point usually solves around 90% of the No Charge conditions on any 3.3L Chrysler mini-van around the world. 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.