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.
1993 Subaru Justy BaseFACTORY OEM SERVICE PROCEDURE
Code 63: Blower Fan Switch
NOTE:
Refer to illustration for ECU connector and terminal identification. See Figure
.
- Disconnect ECU connectors. Turn ignition on. Measure voltage between ground and ECU connector F120, terminal No. 11 (Green/White wire). With blower motor off, voltage should be more than 8 volts. With blower motor on high, voltage should be less than 2 volts. If voltage is as specified, go to next step. If voltage is not as specified, repair faulty heater fan switch or wiring harness connector.
- Turn ignition off. Measure resistance between ground and ECU connector F119, terminal No. 1 (Brown wire). Measure resistance between ground and ECU connector F120, terminal No. 10 (Brown wire). If both resistances are less than 10 ohms, check for poor ECU connector contact. Repair connector and/or wiring harness as necessary. If connector and wiring harness are okay, replace ECU. If either resistance is more than 10 ohms, repair connector and/or wiring harness as necessary.
Factory Service Tools
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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.