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.
2002 Ford ZX2 StandardFACTORY OEM SERVICE PROCEDURE
Test C: One-Touch Down Feature Inoperative (ZX2)
- Turn ignition switch to ON position. Access back of relay box. Relay box is located behind left side of instrument panel. See Figure. Using a voltmeter, measure voltage between ground and backprobe relay box one-touch down control unit 5-pin harness connector C205 terminal No. 3 (Black/White wire). See Figure. If voltage is more than 10 volts, go to next step. If voltage is 10 volts or less, repair open in Black/White wire. See WIRING DIAGRAMS . Retest system operation.
- Turn ignition switch to LOCK position. Using an ohmmeter, measure resistance between ground and backprobe one-touch down control unit 5-pin harness connector C205 terminal No. 5 (Black wire). If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in Black wire. See WIRING DIAGRAMS . Retest system operation.
- Disconnect left front door master window/door lock switch Black 15-pin harness connector C510. Using an ohmmeter, measure resistance in Red/Black wire between left front door master window/door lock switch Black 15-pin harness connector C510 terminal No. 13 and backprobe one-touch down control unit 5-pin harness connector C205 terminal No. 4. See Figure and Figure . If resistance is less than 5 ohms, replace one-touch down control unit. See ONE-TOUCH DOWN CONTROL UNIT under REMOVAL & INSTALLATION. Retest system operation. If resistance is 5 ohms or more, repair open in Red/Black wire. See WIRING DIAGRAMS . Retest system operation.
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.
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