ALTERNATOR TEST 2: Testing The Continuity Of The Battery (+) Circuit
You probably already know, that the one big wire that's attached to the alternator on your Neon (Cirrus, PT Cruiser, Voyage, Caravan, etc) with a nut, is the one that delivers the alternator's charge to the battery and the rest of the vehicle.
This wire (circuit) is protected by an Inline Fusible Link in the older models and a plastic fuse in the newer one. And if this Inline Fusible Link is blown, the alternator's charge will not reach the battery. The Inline Fusible LInk (and the fuse) is located in the engine compartment and is usually located on the starter motor solenoid (consult your repair manual to be sure).
This test will help you determine if this Inline Fusible Link is blown or not with a simple Resistance (Ohms) Test. This test is also known as a Continuity Test.
OK, this is what you'll do:
Disconnect the battery negative cable from the battery negative post. This is super important. Leave the battery positive cable attached to the battery positive post.
If the battery in your specific vehicle is not in the engine compartment but located under the passenger side fender well, you will have to remove the access cover to gain access to the battery and disconnect the battery negative (-) cable from the battery. Do not proceed to the next step without first doing this.
After disconnecting the battery negative (-) cable, select Ohms mode on your trusty multimeter.
As mentioned earlier, the alternator on your car (or mini-van) has only one large diameter wire connected to it by a nut. So probe the stud, to which this large wire is connected to, with the black multimeter test lead.
With the red multimeter test lead, probe the center of the battery positive post on your Neon's (Breeze, Caravan, Stratus, Cirrus) battery.
This Ohms test will produce one of two results:
1.) If the Inline Fusible Link, that protects this circuit, is blown, your multimeter will indicate a reading of OL (which means over limit).
2.) If the Inline Fusible Link (or Fuse) is OK and not blown, your multimeter will register an Ohms reading of 0.5 Ohms or less.
OK, now that the testing part is done, let's take a look at what your results mean:
CASE 1: Your multimeter registered continuity (.9 Ohms or less). This is good, since it indicates that the Fuse protecting this circuit is OK and not blown.
Alright, you can now condemn the alternator as bad. Replace the alternator.
CASE 2: Your multimeter DID NOT register continuity (usually indicated as OL on your multimeter's display). This means that the Fusible Link is blown and this is keeping the alternator's charging output from reaching the battery.
Find the Inline Fusible Link, visually verify that it's blown and replace it. When your done, start the car and retest the voltage at the battery once again with your multimeter.