TEST 3: Jumpering Terminals 3 And 4 Of The PWM Fan Relay Connector
CAUTION: If in TEST 1 you got an amperage draw of 30 or more Amps, do not perform this test. Otherwise, fuse #11 of the Power Distribution Box will get blown!
If you've reached this test section you have:
- Checked the radiator fan motor or motors' circuit has an amperage draw of less than 30 Amps (TEST 1).
- Checked that terminal 4 of the relay's socket has 10 to 12 Volts (TEST 2).
In this section, we'll now check that the radiator fan motor or motors run by jumpering terminal 3 and terminal 4 of the fan relay's connector (socket).
CAUTION: Do not use a jumper wire with male spade terminals that are thicker than the male spade terminals of the PWM fan relay. Using thicker terminals (on the jumper wire) may permanently widen the female terminals in the connector. This could lead to intermittent open-circuit issues, as the female terminals may no longer maintain a tight and secure connection with the relay's male spade terminals. If the terminals of your jumper wire are thicker than the male spade terminals of the PWM fan relay, you can carefully sand them down to reduce their thickness.
IMPORTANT: Before you install the jumper wire, you must be absolutely sure you're jumpering the correct terminals of the PWM fan relay connector. Jumpering the wrong terminals can cause a short-circuit problem in the engine wiring harness or worse - fry the PCM.
Let's get started:
- 1
Disconnect the relay from its electrical connector.
- 2
Locate terminals 3 and 4 of the PWM fan relay.
Terminal 3 connects to a light green (LT GRN) wire.
Terminal 4 connects to a grey (GRY) wire.
IMPORTANT: Before proceeding with this test, ensure that the wire colors match the ones indicated. If there is any discrepancy in wire colors, DO NOT CONTINUE, as this indicates that this tutorial does not apply to your specific vehicle. - 3
Insert one end of your jumper wire into terminal terminal 4 of the relay connector.
This terminal gets 12 Volts from fuse 11 of the Power Distribution Center.
NOTE: The color of the wire that connects to terminal 4 is grey (GRY). If the color of the wire does not match, do not proceed. - 4
Insert the other end of the jumper wire into terminal 3 of the relay connector.
This terminal connects directly to the radiator fan motor.
NOTE: The color of the wire that connects to terminal 3 is light green (LT GRN). If the color of the wire does not match, do not proceed. - 5
The fan motor (single fan motor setup) or fan motors (dual fan motor setup) should run as soon as you've inserted the other end of the jumper wire into terminal 3.
- 6
Remove the jumper wire once you've confirmed the fan motor or motors are working or not.
Let's interpret your test result:
CASE 1: The fan motor ran (Single Fan Motor Setup) or both fan motors ran (Dual Fan Motor Setup). This is the correct and expected test result.
You can conclude that the radiator fan motor or motors are OK if you have:
- Confirmed that the total amperage draw is below 30 Amps (TEST 1).
- Confirmed in this test section that the radiator fan motor or motors ran when jumpering the indicated terminals of the PWM fan relay connector.
If the engine is overheating and the fan motor or motors are not coming ON, you can conclude with this test result that the problem lies elsewhere in the cooling system's electrical system.
IMPORTANT: Now, if in TEST 1 you got an amperage draw of 30 or more Amps, then even if the radiator fan motor or motors ran, it's a bad situation. If you don't replace it or them, the PWM fan relay will get fried (if it hasn't already).
CASE 2: (Single Fan Motor Setup) The fan motor DID NOT run. This usually means that the radiator fan motor is bad.
We're gonna do one more test to make sure, go to: TEST 4: Making Sure The PWM Fan Relay Is Getting Power.
CASE 3: (Dual Fan Motors) Both fan motors DID NOT run. This usually means that the radiator fan motors are bad.
We're gonna do one more test to make sure, go to: TEST 4: Making Sure The Radiator Fan Motor Is Getting Power.
CASE 4: (Dual Fan Motors) One fan motor DID NOT run, the other did run. This means that the radiator fan motor that did not run is bad and needs to be replaced.
No further testing of the fan motors is required. Your next step is to test the PWM fan relay to make it's OK.
TEST 4: Making Sure The Radiator Fan Motor Is Getting Power
In this test section, we're gonna check that 12 Volts are available at the radiator fan motor's connector when terminal 3 and 4 of the relay connector are jumpered together.
If your Neon is equipped with dual radiator fan motors, you'll notice that both fan motors connect to a single-point connector. This single point connector is the one that provides power and Ground to both fan motors.
Unfortunately, I don't have illustrations or photos of the single-point connector used in the dual fan motor setup or the connector for the single fan motor setup. But no worries. Both types of connectors have female terminals and only two wires:
- A light green (LT GRN) wire.
- A black (BLK) wire.
Whether you've got a single or dual radiator fan motor setup on your Neon, you'll be checking the LT GRN wire of the connector for the presence of 12 Volts after jumpering terminals 3 and 4 of the PWM fan relay connector.
Let's get started:
- 1
Disconnect the radiator from its electrical connector (Single Fan Setup).
If your Neon is equipped with dual radiator fan motors, unplug the single-point connector that feeds both fan motors with power and Ground. - 2
Place you multimeter in Volts DC mode.
- 3
Connect the black multimeter test lead on the battery negative (-) terminal.
- 4
Jumper terminals 3 and 4 of the PWM relay connector.
CAUTION: Before inserting the jumper wire, make sure you're jumpering the correct terminals. - 5
Probe the connector's female terminal that connects to the light green wire with the red multimeter test lead.
- 6
You should see 10 to 12 Volts DC.
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 make sure that the connector is supplying Ground to the fan motor or motors. For this test, go to: TEST 5: Making Sure The Radiator Fan Motor Is Getting Ground.
CASE 2: 10 to 12 Volts ARE NOT present. Without this voltage, the fan motor or motors will not run.
The most likely cause of this missing voltage is an open-circuit problem between the connector and the PWM fan relay connector.
TEST 5: Making Sure The Radiator Fan Motor Is Getting Ground
In this last test section, we're gonna check that the fan motor or fan motors are getting Ground from the black (BLK) wire of the radiator fan motor's connector.
The BLK wire belongs to the same connector that has the LT GRN wire you just tested for 12 Volts in TEST 4.
In case you're wondering, the Ground that the BLK wire supplies is a chassis Ground and is available at all times. We'll check for the presence of this Ground with a simple multimeter voltage test.
Let's get started:
- 1
Disconnect the radiator from its electrical connector.
If your Neon is equipped with dual radiator fan motors, unplug the single-point connector that feeds both fan motors with power and Ground. - 2
Place you multimeter in Volts DC mode.
- 3
Connect the red multimeter test lead on the battery positive (+) terminal.
- 4
Probe the connector's female terminal that connects to the black wire with the black multimeter test lead.
- 5
You should see 10 to 12 Volts DC.
Let's interpret your test result:
CASE 1: The multimeter reported 10 to 12 Volts DC. This is the correct and expected test result. It confirms that the BLK wire is indeed supplying Ground to the fan motor or motors.
You can conclude that the radiator fan motor or motors are bad and need to be replaced if you have:
- Checked the fan motor's amperage draw (TEST 1).
- Confirmed that the PWM fan relay is getting power (TEST 2).
- Confirmed that the fan motor or motors did not run when jumpering terminal 3 and 4 of the PWM fan relay (TEST 3).
- Confirmed that the LT GRN wire is delivering 10 to 12 Volts to the fan motor.
- Confirmed that the BLK wire is providing Ground (this test section).
CASE 2: The multimeter DID NOT report 10 to 12 Volts DC. Without this Ground, the fan motor or fan motors are not going to run.
You can conclude that there's an open-circuit problem in the BLK wire between the connector and your Neon's chassis if you have confirmed in TEST 3 that terminal 4 of the PWM relay connector has 10 to 12 Volts present.
If this info saved the day, buy me a beer!
