Testing the blower motor on the 1998, 1999, 2000 and 2001 2.5L Ford Ranger (Mazda B2500) pickup truck is not difficult.
There are two basic tests, the first one is testing the amperage draw of the blower motor, and the second is applying battery power and Ground directly to it via jumper wires.
Both tests are explained in detail and with their test results, you'll be able to find out if your 2.5L Ford Ranger's blower motor is defective (or not).
Contents of this tutorial at a glance:
You can find this tutorial in Spanish here: Cómo Probar El Motor Del Soplador (1998-2001 2.5L Ford Ranger) (at: autotecnico-online.com).
The following tutorials may come in handy:
- How To Test The Blower Motor Switch (1998-2000 2.5L Ford Ranger).
- How To Test The Blower Resistor (1998-2000 2.5L Ford Ranger).
NOTE: You can find the blower motor circuit diagram here: Blower Motor Circuit Diagram (1998-2000 2.5L Ford Ranger).
Blower Motor Basics
The blower motor is a very simple electrical component. Its connector has two wires coming out of it.
The pink with white stripe (PNK/WHT) wire provides battery power. The orange with black stripe (ORG/BLK) wire provides Ground.
To get a good look at the entire circuit, take a look at the blower motor circuit diagram here: Blower Motor Circuit Diagram (1998-2000 2.5L Ford Ranger).
The blower motor on the 1998-2000 2.5L Ford Ranger gets power from the blower motor relay in the under hood fuse box. The blower motor relay in turn, gets power from the 40 Amp BLOWER MOTOR FUSE located in the under hood fuse box.
When the blower motor fails, it usually fails in one of two ways:
- The blower motor will stop working completely.
- The blower motor will run, but run with a lot of bearing noise.
Thankfully, testing the blower motor is a pretty simple process.
TEST 1: Testing The Amperage Draw Of The Blower Motor
As your 1998-2001 Ford Ranger's blower motor ages, it's gonna' use more amperage (current). Eventually, the amount of current that it uses will cause problems.
One of these problems, caused by this excessive current draw, is the overloading of the blower resistor and blower motor switch.
To find out how much amperage the blower motor is drawing, we can do a simple multimeter resistance test and then using Ohm's law, calculate it's amperage draw (Ohms Law: Amps=Volts ÷ Ohms).
This simple multimeter amperage draw test is very accurate and will tell us if the blower motor is defective or not.
NOTE: If you don't have a multimeter and need to buy one, check out my recommendations here: Buying A Digital Multimeter For Automotive Diagnostic Testing.
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). 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.
NOTE: The maximum amperage draw is 40 Amps.
Let's take a look at your test results:
CASE 1: The amperage draw is less than 40 Amps. This is the correct test result and to lets you know that the amount of current that the blower motor, on your 2.5L Ford Ranger (Mazda B2500) is using is normal.
CASE 2: The amperage draw is at 40 Amps or more. The blower motor is defective and needs to be replace.
This excessive current draw is usually do too: debris seizing the motor, bad bearings, worn brushes, burnt commutator, etc.