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 MANUALSMERCURY1998MOUNTAINEER 5.0 P, AWDREPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT CARSECTION 18 (DEFOGGER - REAR WINDOW)COMPONENT TESTINGREAR DEFOGGER RELAY
1998 Mercury Mountaineer 5.0 P, AWD
Rear Defogger Relay
1998 Mercury Mountaineer 5.0 P, AWDSECTION Rear Defogger Relay
WARNING: This page is about a different car, the 1997 Ford Expedition. However, it is still accessible from the selected car via links, so may be relevant.
- Unplug relay located in fuse relay panel under right side of instrument panel. Check continuity between relay terminals No. 30 and 87A. See Fig 1 . Continuity should exist. Check continuity between relay terminals No. 30 and 87. Continuity should not exist. Replace relay if not as specified.
- Using 2 jumper wires, apply battery power and ground to relay terminals No. 85 and 86. Using a third jumper wire, apply battery power to relay terminal No. 30. With power applied, measure voltage between ground and relay terminals No. 87 and 87A. Voltage should not exist at terminal No. 87A and battery voltage should exist at terminal No. 87. Replace relay if not as specified.
RENDER: 1.0x
NO RELATED
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- β’ You smell fuel, burning insulation, or see smoke.
- β’ Brakes feel soft, pull hard to one side, or make grinding noises.
- β’ The engine overheats, stalls repeatedly, or misfires under load.
- β’ You are missing required tools, torque specs, or safe lifting equipment.
- β’ You are not confident in the next step or safety outcome.