Blower Fan Housing Components (Ford)
A – Blower fan
B – Fan resistor
C – Fan motor connector
D – High speed fan relay
Checking the blower motor resistor
| Resistance | Resistor contacts |
| 0.38 Ohm | 3 and 4 |
| 0.69 Ohm | 3 and 2 |
| 1.69 Ohm | 1 and 2 |
| 2.76 Ohm | 1 and 4 |
Checking the Blower Fan Speed Switch (Ford)
| Switch position (speed) | The circuit between the contacts is closed |
| Low | – |
| Second | 2 and 3 |
| Third | 2 and 3, 2 and 4, 3 and 4 |
| High | 2 and 4, 2 and 1, 4 and 1 |
Checking the Blower Fan Speed Switch (Mazda)
| Switch position | Contact |
| Any | F |
| First position | E |
| Second position | C |
| Third position | A or D |
| The fourth position | B or D |
On Mazda models, the fan relay is located in the right front corner of the engine compartment. Ford Probe models use two relays - 1993 models have the low speed relay mounted in front of the radiator and later models have the low speed relay mounted in the left rear corner of the engine compartment. The high speed fan relay is located in the fan housing itself.
The blower fan is located under the glove compartment.
Examination
1. If the blower fan does not work, first check the connections of the connectors in the blower circuit. Check the engine fuse (15A) in the interior fuse panel and the heater fuse (40A) in the underhood fuse/relay panel.
2. Locate the fan relay. Remove the relays and check if they are functioning properly (see subsection 12.5). Replace the relay if necessary.
3. Check how the fan operates in all modes.
4. If the fuses and relays are OK and the fan does not work, test the fan itself.
5. Connect the tester to the blue/red (Mazda) or white (Ford) terminal. The tester should read at least 10 V (ignition on, fan mode switch in any position except OFF). If not, there is a problem with the fan circuit.
6. If power is supplied to the fan and it does not work, connect the blue/white (Mazda) or black/orange (Ford) wire to ground on the vehicle body using a jumper wire. If the fan still does not work, it needs to be replaced. If the fan is working, this means that there is a fault in the fan grounding circuit.
7. If the fan works, but not in all modes, check the fan resistor, which is located on the fan shroud.
8. Remove the resistor and inspect it for damage. Check the resistor with an ohmmeter (see figureChecking the blower motor resistor). Replace the resistor if necessary.
9. If the resistor is functioning properly, remove the heater control panel. On Probe models, disconnect the wires from the back of the blower fan switch and check the resistance of the switch (see the figure Testing the Blower Fan Speed Switch (Ford). On Mazda models, connect a voltmeter to the switch terminals and check if voltage is reaching the terminals (see the figure Testing the Blower Fan Speed Switch (Mazda). If the switch is faulty, replace it.