Mazda MX-5 NA silhouetteMX-5 NA

TROUBLESHOOTING GUIDE — Blower motor (Steps 3–5)

U-8prose procedure
Continued from U-7

Step 3

  1. 1
    Turn the ignition switch ON.
  2. 2
    Turn the blower switch and A/C switch OFF.
  3. 3
    Measure the voltage at the terminal-wires of the resistor assembly.
    Illustration of the blower-resistor assembly with its 1-pin and 4-pin connectors highlighted. Pinouts shown: 1-pin connector with wire (L/R); 4-pin connector with wires (L/G), (L/R), (L/W), (L/Y). Used to measure voltages at the resistor terminals.
    05U0UX-008

Step 3 — Resistor assembly terminal voltages

(L/R) (1-pin connector)
Voltage12V
ActionNext, check wire (L/W)
(L/R) (1-pin connector)
Voltage0V
ActionReplace blower motor
(L/W)
Voltage12V
ActionNext, check wire (L/R)
(L/W)
Voltage0V
ActionReplace resistor assembly
(L/R) (4-pin connector)
Voltage12V
ActionNext, check wire (L/G)
(L/R) (4-pin connector)
Voltage0V
ActionReplace resistor assembly
(L/G)
Voltage12V
ActionNext, check wire (L/Y)
(L/G)
Voltage0V
ActionReplace resistor assembly
(L/Y)
Voltage12V
ActionGo to Step 4
(L/Y)
Voltage0V
ActionReplace resistor assembly

Step 4

  1. 1
    Turn the ignition switch ON.
  2. 2
    Turn the blower switch to the fourth position.
  3. 3
    Measure the voltage at terminal-wire (B) of the blower switch connector.
    Illustration of the blower switch connector with terminal-wire (B) — Black — highlighted for voltage measurement to body ground.
    05U0UX-009

Step 4 — Blower switch terminal (B) voltage

(B)
Voltage0V
ActionGo to Step 5
(B)
Voltage12V
ActionRepair wire harness (Blower switch—Body ground)

Step 5

  1. 1
    Turn the ignition switch ON.
  2. 2
    Turn the blower switch and A/C switch OFF.
  3. 3
    Measure the voltage at the terminal-wires of the blower switch connector.
    Illustration of the blower switch connector showing the four terminal-wires (L/G), (L/Y), (L/R), (L/W) along the connector for voltage measurement between the resistor assembly and the blower switch.
    05U0UX-010

Step 5 — Blower switch terminal voltages

(L/W)
Voltage0V
ActionRepair wire harness (Resistor assembly—Blower switch)
(L/W)
Voltage12V
ActionNext, check wire (L/R)
(L/R)
Voltage0V
ActionRepair wire harness (Resistor assembly—Blower switch)
(L/R)
Voltage12V
ActionNext, check wire (L/G)
(L/G)
Voltage0V
ActionRepair wire harness (Resistor assembly—Blower switch)
(L/G)
Voltage12V
ActionNext, check wire (L/Y)
(L/Y)
Voltage0V
ActionRepair wire harness (Resistor assembly—Blower switch)
(L/Y)
Voltage12V
ActionReplace blower switch
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See also

Step 4 · Step 5

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