Mazda MX-5 NA silhouetteMX-5 NA

TROUBLESHOOTING GUIDE — Symptom: Magnetic clutch does not operate.

U-9flowchart

Normal operation of magnetic clutch

The magnetic clutch is supplied with battery voltage as shown: 1. A/C and blower motor switches are turned ON. 2. ECU receives signal that A/C and blower switches are ON and creates ground circuit. 3. A/C relay is magnetized and contact is closed. 4. Battery voltage is applied to magnetic clutch and clutch locks.

Magnetic clutch troubleshooting

  1. 1
    Check the following fuses.
    If the fuses are OK, go to Step 2.
    If a fuse is burned, check for a short circuit in the harness before replacing it.
    Line drawing of the fuse box and main fuse block showing rows of fuse positions. The WIPER 20A fuse is labeled at the left (fuse box) and the AD FAN 20A fuse is labeled at the right (main fuse block).
    05U0UX-084
  2. 2
    Run the engine at idle. Turn the A/C switch and blower switch ON. Measure the voltage at terminal-wire (B/R) of the magnetic clutch connector.
    Engine compartment photo showing voltmeter probes connected at the (B/R) terminal-wire of the magnetic clutch connector. A meter symbol and (B/R) label are drawn in the lower-left corner.
    05U0UX-012
  3. 3
    Disconnect the thermoswitch connector. Check for continuity of the thermoswitch.
    Photo of the thermoswitch with an ohmmeter (Ω) connected across its terminals to check continuity. Lead wires from the meter are routed to the disconnected thermoswitch connector.
    05U0UX-013

Step 1 — Fuses to check

WIPER
Amperage20A
LocationIn fuse box
AD FAN
Amperage20A
LocationIn main fuse block

Step 2 — Voltage at (B/R) terminal

(B/R)
Voltage12V
ActionGo to Step 3
(B/R)
Voltage0V
ActionGo to Step 5

Step 3 — Thermoswitch continuity

Yes
ActionGo to Step 4
No
ActionReplace thermoswitch
Support our work!

See also

U-7TROUBLESHOOTING GUIDE — Blower motor does not operateSection F

Search Manual

Search pages, specs, and procedures