Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
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HOMESERVICE MANUALSMAZDA1999626 ES, 2.5 D, STANDARDREPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT CARSECTION 492 (SYMPTOM TROUBLESHOOTING [ENGINE CONTROL SYSTEM BP, BP WITH TC))ENGINE CONTROL SYSTEM OPERATION INSPECTIONCOOLING FAN CONTROL OPERATION INSPECTION (BP WITH TC)
1999 Mazda 626 ES, 2.5 D, Standard
Cooling Fan Control Operation Inspection (BP WITH TC)
1999 Mazda 626 ES, 2.5 D, StandardSECTION Cooling Fan Control Operation Inspection (BP WITH TC)
WARNING: This page is about a different car, the 2005 Mazda MX-5 Miata. However, it is still accessible from the selected car via links, so may be relevant.
- Connect the WDS or equivalent to DLC-2.
- Access the ECT PID.
- Verify that the ECT PID is below 100°C {212°F}
- Verify that the fan motor No.1 and No.2 do not operate.
- If the cooling fans are operating, inspect for following:
- Short to GND circuit in wiring between A/C switch and PCM terminal 4F
- Short to GND circuit in wiring between fan relay No.1 and PCM terminal 2B
- Short to GND circuit in wiring between fan relay No.2 and PCM terminal 2C
- Short to GND circuit in wiring between fan relay No.3 and PCM terminal 2C
- Fan relay No.1 stuck close
- If the cooling fans are operating, inspect for following:
- Start the engine and warm up it to ECT PID is above 100°C {212°F}
- Verify that fan motor No.1 and No.2 operate.
- If the fan motor No.1 and No.2 do not operate inspect for following:
- Open circuit in wiring between PCM terminal 2B and fan relay No.1
- Open circuit in wiring between battery positive terminal and fan relay No.1
- Fan relay No.1 stuck open
- If the fan motor No.1 does not operate inspect for following:
- Open circuit between fan relay No.1 and GND through fan motor No.1
- Fan motor No.1 malfunction
- If the fan motor No.2 does not operate inspect for following:
- Open circuit between fan relay No.3 and GND through fan motor No.2
- Fan motor No.2 malfunction
- If the fan motor No.1 and No.2 do not operate inspect for following:
- Verify that the fan motor No.1 and No.2 operate high speed while the A/C is operating.
- If the fan motor No.1 and No.2 do not operate high speed, inspect for following:
- Open circuit between A/C switch and PCM terminal 4F
- Open circuit between PCM terminal 2C and fan relay No.2
- Open circuit between PCM terminal 2C and fan relay No.3
- Open circuit between battery positive terminal and fan relay No.2
- Open circuit between battery positive terminal and fan relay No.3
- Open circuit between fan relay No.2 and GND
- Fan relay No.2 stuck open
- Fan relay No.3 stuck open
- If the fan motor No.1 does not operate high speed, inspect for following:
- Open circuit between fan relay No.2 and fan motor No.1
- Open circuit between fan relay No.3 and fan motor No.1
- Fan motor No.1 malfunction
- If the fan motor No.2 does not operate high speed, inspect for following:
- Open circuit between fan relay No.2 and fan motor No.2
- Open circuit between fan relay No.3 and fan motor No.2
- Fan motor No.2 malfunction
- If the fan motor No.1 and No.2 do not operate high speed, inspect for following:
RENDER: 1.0x
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.