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.
1989 Isuzu I-Mark LSFACTORY OEM SERVICE PROCEDURE
ECM Ignition Power Supply
- Main relay is activated by ignition switch and supplies battery power to ECM.
- On I-Mark, main relay is powered through 10A fuse (No. 13) in fuse box (left side of dash). Main relay should always have power at Red/White wire from 20 amp fuse (No. 14) in fuse box.
Factory Service Tools
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
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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.