1989 Mercury Grand Marquis Service and Repair Manual

This factory service and repair manual for the 1989 Mercury Grand Marquis documents a car built in two-door and four-door sedan form, sold as Base, GS or LS, and powered by one of two naturally aspirated overhead-valve V8s — the 5.0L of 302 cubic inches or the 5.8L of 351, both on gasoline. Fuel, ignition and emissions procedures are given per engine; brake, suspension, steering and body electrical procedures apply to both, with specifications, torque values, wiring diagrams and diagnostics kept in their own sections.

Engines covered

• 5.0L V8 (302 cu in) — OHV, naturally aspirated, gasoline
• 5.8L V8 (351 cu in) — OHV, naturally aspirated, gasoline

Body styles covered

• 2-door sedan
• 4-door sedan

Trims covered

• Base
• GS
• LS

Known issues on the 1989 Grand Marquis. Two recalls appear on the federal record. One describes an ignition switch capable of shorting inside itself, which can overheat, smoke and start a fire around the steering column. The other covers replacement fuel pumps whose diaphragms may leak gasoline and raise a fire risk. Owners have logged 63 complaints, the largest groups being 18 on the electrical system, 16 on speed control and six on the power train — the switch, harness, speed control and transmission circuits that the wiring diagrams and diagnostic charts in this manual address.