Testing the blower motor, on the 2000 Dodge Dakota, involves two basic tests and in this tutorial I'll explain them both. These two tests will help you find out if it's defective or not.
I'm also gonna' show you where to buy it and save a couple of bucks on it.
- Blower Motor Basics.
- TEST 1: Testing The Amperage Draw Of The Blower Motor.
- TEST 2: Applying Power And Ground To The Blower Motor.
- Where To Buy The Blower Motor.
- More 4.7L Dodge Tutorials.
NOTE: You can find the 5 terminal blower motor resistor block test (for the 2000 Dodge Dakota) here: How To Test The 5 Terminal Blower Motor Resistor (2000 Dodge Dakota).
You can find this tutorial in Spanish here: Cómo Probar El Motor Del Soplador (2000 Dodge Dakota) (at: autotecnico-online.com).
Blower Motor Basics
You'll notice that the blower motor's engine wiring harness connector has female terminals and that the connector on the blower motor itself has male spade terminals.
The wiring harness connector (the one with the female terminals) has a dark green (DK GRN) and a grey (GRY) wire.
The DK GRN wire is the one that feeds battery power to the blower motor. This battery power comes from the #5 40 Amp fuse (of the under-hood fuse/relay box) via the HEVAC Relay. The HEVAC Relay is located in the under-hood fuse/relay box.
The GRY wire is the one that feeds ground to the blower motor. This ground is channeled by the blower motor resistor and the blower motor switch to chasis ground.
When the blower motor fails (or starts to fail), it will do one of 2 things:
- Stop working completely.
- Run, but run with a lot of noise.
TEST 1: Testing The Amperage Draw Of The Blower Motor
The first thing we're gonna' do is to check the amperage draw of your Dodge Dakota's blower motor.
Why test the amperage draw of the blower motor? Because in certain cases, the blower motor runs but draws too much amperage. This high amperage draw will blow the blower motor fuse or fry the blower motor resistor.
Although this is probably one of the most overlooked tests (when diagnosing a blower motor) it's an easy one that only requires a multimeter resistance test.
Once we have the blower motor's resistance value, we'll use Ohm's Law to calculate it's amperage draw (Ohms Law: Amps=Volts ÷ Ohms).
Let's get started:
Disconnect the blower motor from its electrical connector.
Place your multimeter in Ohms mode.
Measure the resistance of the blower motor with your multimeter. You'll be testing across the blower motor's connector and not the vehicle's wiring harness connector.
Divide 12.5 by the resistance value you got in step 3 (12.5 is the battery voltage 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 .4 Ohms. This is what the math would look like: 12.5 ÷ .4 = 31.25 and this would translate to 31.25 Amps.
Let's take a look at your test results:
CASE 1: Your test result resulted in a calculation of under 40 Amps. This is the correct and expected test result and let's you know that the blower motor amperage draw is within specification.
The next step is to manually apply power and ground to the blower motor itself. For this test go to: TEST 2: Applying Power And Ground To The Blower Motor.
CASE 2: Your test result resulted in a calculation of 40 Amps or more. This test result tells you that the blower motor, on your 2000 Dodge Dakota, is defective and needs to be replaced.