Mazda MX-5 NA silhouetteMX-5 NA

RELAY

T-19prose procedure

4-TERMINAL NORMALLY OPEN RELAY (NO RELAY)

Inspection

The relays listed below are 4-terminal normally open (NO) relays. • Horn relay • Headlight relay • TNS relay • Cooling fan relay

Headlight relay and cooling fan relay

Headlight relay and cooling fan relay inspection

  1. 1
    Check continuity between terminals 3 and 4.
    Ohmmeter checking continuity between terminals 3 and 4 of the headlight relay / cooling fan relay; inset shows 4-pin terminal layout with positions 1, 2, 3, 4.
    05U0TX-275
  2. 2
    If not as specified, replace the relay.
  3. 3
    If correct, go to Step 4.
  4. 4
    Apply 12V to terminal 1 and ground terminal 2. Check for continuity between terminals 3 and 4.
    Battery applying 12V to terminal 1 and ground to terminal 2 of the relay; ohmmeter checking continuity between terminals 3 and 4.
    9MU0TX-027
  5. 5
    If not as specified, replace the relay.

Headlight/cooling fan relay continuity — Step 1

3—4
ContinuityNo

Headlight/cooling fan relay continuity — Step 4 (12V to 1, gnd 2)

3—4
ContinuityYes

Horn relay and TNS relay

Horn relay and TNS relay inspection

  1. 1
    Check continuity between terminals 1 and 3.
    Ohmmeter checking continuity between terminals 1 and 3 of the horn relay / TNS relay (3-prong relay shown).
    05U0TX-276
  2. 2
    If not as specified, replace the relay.
  3. 3
    If correct, go to Step 4.
  4. 4
    Apply 12V to terminal 2 and ground terminal 4. Check for continuity between terminals 1 and 3.
    Battery applying 12V to terminal 2 and ground to terminal 4 of the relay; ohmmeter checking continuity between terminals 1 and 3.
    05U0TX-277
  5. 5
    If not as specified, replace the relay.

Horn/TNS relay continuity — Step 1

1—3
ContinuityNo

Horn/TNS relay continuity — Step 4 (12V to 2, gnd 4)

1—3
ContinuityYes
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