In this tutorial, I'll guide you on how to test the radiator fan motor on the 1995-1996 2.0L SOHC Neon. The cool part is, you don't need an automotive scan tool or any other expensive diagnostic equipment to test the radiator fan motor.
Through this straightforward testing process, you'll be able to easily determine whether the fan motor is functioning correctly or if it's in need of replacement.
Content of this tutorial:
You can find this tutorial in Spanish here: Cómo Probar El Motor Del Ventilador Del Radiador (1995-1996 2.0L SOHC Dodge/Plymouth Neon) (at: autotecnico-online.com).
APPLIES TO: This tutorial applies to the following vehicles:
- 2.0L Dodge Neon: 1995, 1996.
- 2.0L Plymouth Neon: 1995, 1996.
Symptoms Of A Bad Radiator Fan Motor
As the radiator fan motor ages, its bearings/bushings wear out. Not only that but dirt, dust, and debris can accumulate inside the motor housing. This accumulation of dirt and wear on the bearings/bushings increases friction within the motor.
More friction means the motor has to work harder to overcome it, which results in higher amperage draw. Increased friction also generates heat, which can further accelerate wear and reduce the efficiency of the fan motor. Eventually, these factors will lead to a radiator fan motor that no longer functions.
Here are some of the symptoms you'll see when the radiator fan motor stops working:
- Overheating Engine: The primary job of the radiator fan is to keep the engine cool. If it's not working, the engine will overheat.
- Coolant Boiling Over: If the fan isn’t cooling the engine, the coolant can get too hot and boil over and leak from the coolant reservoir or radiator.
- Warning Lights: The temperature light on the dashboard will illuminate or the temperature gauge will max out to indicate overheating from the non-functioning radiator fan.
- Unusual Sounds: Sometimes, a failing radiator fan motor might produce unusual noises if it's trying to run but encountering resistance.
TEST 1: Checking The Fan Motor's Amperage Draw
The first thing we'll do is determine the amount of amperage the radiator fan motor is drawing. If the fan motor is fried, your test results will indicate that it's drawing 30 or more Amps.
Determining the amperage draw of the radiator fan motor is an easy and straightforward thing. The test primarily involves measuring the internal resistance of the fan motor, then applying Ohm's Law to determine the amperage draw of the radiator fan motor. In the test instructions below, I'll explain the whole process in detail.
These are the test steps:
Disconnect the fan motor from its electrical connector.
Set your multimeter to Ohms mode.
Measure the fan motor's resistance by probing its two terminal with the multimeter test leads.
NOTE: It's important that the fan blades do not turn while you're resistance testing the fan motor.
Write the Ohms value down on a piece of paper once the Ohms reading on your multimeter stabilizes.
Divide 12.5 by your resistance value.
The result of this calculation is the amount of amperage the fan motor is using.
To be a little more specific: Let's say that the resistance reading was 0.4 Ohms. This is what the math would look like: 12.5 ÷ 0.4 = 31.25 and this would translate to 31.25 Amps.
Let's interpret your test result:
CASE 1: The amperage draw is under 30 Amps. This is the correct and expected test result.
The next step is to check that the radiator fan motor relay is getting 10 to 12 Volts. For this test go to: TEST 2: Making Sure The Radiator Fan Relay Is Getting 12 Volts (Control Circuit).
CASE 2: The amperage draw is at or above 30 Amps. This tells you that radiator fan motor has a lot of wear and tear (internally) and you can conclude it's bad and needs replacement.
Getting an amperage draw result of 30 Amps or more is a tell-tale sign of heavy internal wear and tear within the radiator fan motor. Even if the fan motor runs, it’s gonna blow its 30 Amp fuse in the Power Distribution Center fuse/relay box (due to this high amperage draw).
If the radiator fan fuse blows, the fan won't run due to a lack of current and the engine is going to overheat. So, even if the fan motor runs, you should replace it to avoid costly engine overheating issues.
TEST 2: Making Sure The Radiator Fan Relay Is Getting 12 Volts (Control Circuit)
In this test section, we'll make sure that the radiator fan relay's load circuit is getting power. The radiator fan relay is located in the Power Distribution Center fuse/relay box located in the engine compartment (behind the battery).
You'll remove the radiator fan relay and check that the female terminal labeled with number 1 in the illustration 1 of 2 (in the image viewer above) has 10 to 12 Volts DC.
In case you're wondering what the 'load circuit' is: the load circuit is the part of the relay that carries the current to the intended component (the radiator fan motor in our case). When the control circuit activates the relay, a switch in the load circuit closes, allowing 12 Volts to flow to the component that the relay is controlling.
NOTE: You can find the descriptions/locations of all the fuses and relays of the Power Distribution Center here: Power Distribution Center (1995-1996 Dodge/Plymouth Neon).
Let's get started:
Remove the radiator fan relay from the Power Distribution Center.
Connect the black multimeter test lead to the negative (-) battery post.
Probe the female terminal labeled with the number 1 with the red multimeter test lead (using the appropriate too).
IMPORTANT: Avoid inserting the tip of the multimeter test lead directly into the female terminal as this can damage it. Instead, use an adapter whose tip will easily fit into (or probe) the female terminal inside the cavity (slot) of the fuse/relay box.
Your multimeter should give you a reading of 10 to 12 Volts DC.
NOTE: No need to turn the key to the RUN position, since power is available at all times. This voltage comes from FUSE 11 (see illustration 2 of 2 in the image viewer above).
Let's interpret your test result:
CASE 1: 10 to 12 Volts are present. This is the correct and expected test result. Your next step is to go to: TEST 3: Making Sure The Radiator Fan Relay Is Getting Power (Control Circuit).
CASE 2: 10 to 12 Volts ARE NOT present. This usually means that the radiator fan motor fuse (FUSE 11) is blown.
Check and replace the fuse (if necessary) and repeat the test. Once power is restored, go to: TEST 3: Making Sure The Radiator Fan Relay Is Getting Power (Control Circuit).