2003 Mercury Grand Marquis: common problems

Owners of the 2003 Mercury Grand Marquis filed 362 complaints with NHTSA, most often about exterior lighting and electrical system. Details by component below, with sources.

Key figures

Owner complaints: 362
involving a crash: 22

What fails most often

1 Exterior lighting 57% of all complaints
2 Electrical system 14% of all complaints
3 Steering 8% of all complaints
4 Suspension 8% of all complaints
5 Vehicle speed control 7% of all complaints
6 Engine and cooling 4% of all complaints
7 Powertrain 3% of all complaints
8 Air bags 3% of all complaints

Circle size and colour show each component’s share of NHTSA complaints. Schematic only, not a drawing of the exact model.

Exterior lighting: 207 complaints (57% of all), 5 of them with a crash reported by the owner.
Electrical system: 51 complaints (14% of all), 4 of them with a crash reported by the owner.
Steering: 28 complaints (8% of all).
Suspension: 28 complaints (8% of all).
Vehicle speed control: 27 complaints (7% of all), 13 of them with a crash reported by the owner.

Engines and transmissions

US-market versions per EPA. On the right: how many NHTSA complaints name this engine or transmission type.

4.6 L · petrol · 8 cylnamed in 1 complaints
automatic, 4-speed

Drive: RWD

Symptoms owners describe

How many of the 362 NHTSA complaints mention each symptom (automatic count from complaint text; one complaint can mention several).

headlights and tail lights161 · 44%
warning lights, check engine16 · 4%
knocking, grinding or other noise12 · 3%
steering or power steering problems12 · 3%
unintended acceleration10 · 3%
rust, corrosion8 · 2%
stalls while driving8 · 2%
seat belts6 · 2%
smoke, burning smell, fire6 · 2%
vibration5 · 1%

Components owners complain about

Component	Owner complaints	involving a crash
Exterior lighting	207	5
Electrical system	51	4
Steering	28	0
Suspension	28	0
Vehicle speed control	27	13
Engine and cooling	13	1
Powertrain	12	0
Air bags	11	3
Visibility	10	0
Wheels	10	0
Structure	9	1
Service brakes	7	2
Fuel system	6	0
Engine	5	1

What owners report

Short excerpts of NHTSA complaints in the original wording. These are owner statements not verified by NHTSA; personal data removed.

Its the LCM L(IGHT CONTROL MODULE)...HEAD LIGHTS went out on me one night coming down [XXX] causing me to wreck in a ditch and hitting a light pole INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)
Exterior lighting · crash · 2024-01-14 · NHTSA complaint #11565456
Car hit metal post and tree knocking them down and dragging the tree 50 to 60 feet before stopping with my foot still on the break. Car had stopped accelerating. I turned off the ignition. This unintended acceleration had happened before. Two different dealers attempted to fix the problem.
Electrical system · crash · 2023-01-20 · NHTSA complaint #11502872
The contact stated that while driving 45 mph at night, the low beam headlights shut off and the contact crashed into a ditch. The front and rear passengers tires were damaged. The contact was not injured. The dealer was informed about the failure and they stated that they never heard of that before.
Exterior lighting · crash · 2010-10-22 · NHTSA complaint #10361763
While driving approximately 55 mph the vehicle was involved in a single car crash in which the air bags did not deploy and the driver was thrown from the seatbelt into the rear passenger seat. The police appeared on the scene and the driver was reported injured.
Air bags · crash · 2010-10-05 · NHTSA complaint #10359226
Two problems I have with this car is that the hubcaps are crap, they rattle when I drive, one came off completely and I had to stop and get it. I am now looking to replace them. The second problem is my major concern and that is lcm(lighting control module) I had an accident (minor) but I did damage the front end.
Exterior lighting · crash · 2010-09-13 · NHTSA complaint #10355126
Sudden acceleration in a 2003 mercury grand marquis. This happened after putting the vehicle in drive, it took off at an excessive rate of speed crossed a street and jumped two curbs about 15 inches high within 5 or 6 seconds.
Vehicle speed control · crash · 2010-01-29 · NHTSA complaint #10303107
Dt*: the contact stated while parked with the ignition on; the vehicle suddenly lurched forward without warning. The brakes were depressed and the ignition was turned off, which stopped the vehicle after it traveled 60 ft. This had occurred on numerous occasions.
Vehicle speed control · crash · 2006-11-17 · NHTSA complaint #10173741
2003 mercury grand marquis experiencing problems with the braking system. The consumer's foot would make contact with the brake and the accelerator pedal at the same time. The bake and the accelerator pedals are less than 3 inches apart. The consumer experienced a minor parking accident due to this problem.
Structure · crash · 2005-05-06 · NHTSA complaint #10120410

When owners complained

NHTSA complaints by filing year. The peak shows at what age the problems show up most.

20022
200327
200414
20059
20067
20079
20089
200920
201039
201120
201220
201320
201442
201525
201628
201721
20188
20198
20204
20214
20227
20237
20248
20253
20261

Comparison

By complaint count this model year ranks 1,103 of 36,656 model years in the NHTSA data (top 3% most complained about).

On average one model year of the Grand Marquis has 117 complaints (34 years in the data). This year has 362, above average.

What to check before buying

Exterior lighting. Headlamps, leveling, sensors and mounts after a frontal hit.
Electrical system. Scan all modules, test the battery and alternator, inspect connectors near the impact zone.
Steering. Steering play, power assist, rack and tie rods after a wheel impact.
Suspension. Wheel alignment, control arms, subframe, even tire wear.

Other years of this model

Questions and answers

What are the most common problems with the 2003 Mercury Grand Marquis?

Owner complaints to NHTSA most often mention: exterior lighting, electrical system, steering. Total complaints: 362. The most frequent symptoms in complaint texts: headlights and tail lights (44%), warning lights, check engine (4%), knocking, grinding or other noise (3%).

How many service bulletins (TSB) were issued for the 2003 Mercury Grand Marquis?

NHTSA lists 0 manufacturer service bulletins for this year. A bulletin tells dealers how to diagnose or fix a known issue; it is not a recall.

Should I buy a 2003 Mercury Grand Marquis from a US auction?

Owner complaints describe defects, not crash damage. Before bidding, check the components listed above and review the lot photos: VinWind builds a report of visible and hidden damage by VIN.

Other 2003 models

Read also

Sources: public NHTSA data (USA): service bulletins and owner complaints; YouTube: links to videos credited to their authors. Complaints are owner statements not verified by NHTSA, and describe defects rather than crash damage. Data updated 2026-11-05.