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.
1991 Lexus ES 250 AutomaticFACTORY OEM SERVICE PROCEDURE
Cooling Fan Control System: Notes
- Coolant temperature should be less than 185°F (85°C) on ES250 or less than 181°F (83°C) on LS400. Turn ignition on. Cooling fans should not rotate. If cooling fans rotate, check cooling fan relays and water temperature sensor (ES250) or water temperature switch (LS400). Check for damaged connectors and an open circuit between cooling fan relay and water temperature sensor/switch.
- Disconnect water temperature sensor/switch connector. See Fig 1 or Fig 2. With ignition on, cooling fans should operate. If cooling fans do not operate, check engine main relay and fuse. Check cooling fan motors. Also check cooling fan relays and water temperature sensor/switch. Check for damaged connectors or an open circuit between cooling fan relay and water temperature sensor/switch. If okay, go to step 3) for ES250 or step 4) for LS400.
Factory Service Tools
Use the Manual With the Right Hardware
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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.
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