Under the Hood
---- — My car is a 2005 Mercury Grand Marquis. My headlights will go off after driving a half-mile. The directional and brake lights still work, and if I pull the directional lever towards me, the headlights will briefly come back on, while held. If I shut off the car, the lights will be OK again, but only for a short time.
I have been told that this happens on Mercury cars from 2003 to 2008. I have been told that it is not fixable and has an expensive part that needs to be replaced. Your comments would be appreciated.
Other than losing one’s brakes, or encountering a stuck-open throttle, this has to be one of the creepiest situations one can encounter. At 70 mph, we travel 102 feet per second. Even with great reaction time and good brakes, you’d cover about two-thirds the length of a football field in darkness before bringing the car to a stop.
The Internet is abuzz about Grand Marquis, Crown Victorias and Town Cars of this vintage having this problem. In 2008, the National Highway Traffic Safety Administration investigated the issue. Ford reported 2,074 incidences of headlight failure during the first three years of vehicle operation, with 214 of these occurring while underway.
Defective solder joints in the lighting control module, or LCM, were deemed the main culprit, but one must also consider that using higher-wattage aftermarket headlight bulbs could trigger a protective shutdown.
As bad as this sounds, the average warranty percentage of headlight failures was only 0.05 percent, leading the NHTSA to close the investigation. The NHTSA reminds us that closing an investigation does not constitute a finding that a safety-related defect does not exist, and they will monitor the issue and take further action if warranted by circumstances.
In a nutshell, this is a rare problem, but 0.05 percent of a whole bunch of cars sold is more than just a few, and the fleet has aged considerably. Renewal of the pricey LCM typically resolves the issue, after a test of three circuit paths. There are quite a few businesses rebuilding LCMs for $50 to$100 with a lifetime warranty; this would be my solution choice. Check eBay and local sources.
The part, located above the gas pedal, is fairly easy to remove and reinstall. The problem is the downtime while it is in route to and from the repair facility.
I called Lincoln Motor Co. owner services — Mercury is now defunct — and asked if a goodwill gesture or policy adjustment was in the works. I was told affected owners should contact them and that issues would be addressed on a case-by-case basis. I’d be sure to mention that I’d have a hard time trusting one of their current or future products were they not to stand with me on such a serious safety concern.
I think Ford is presently building some really great vehicles. Hopefully they might inspire you to feel good about this one again — and come back for another when you’re ready for a new one.
You mentioned the headlights returned as you pulled back on the turn signal lever. This is called flash-to-pass, and in these vehicles, headlight power is supplied via a different path than through the LCM. This could be a lifesaver, if one can remember to quickly execute the maneuver during an unexpected lights-out emergency.
Brad Bergholdt is an automotive technology instructor at Evergreen Valley College in San Jose, Calif. Readers may send him email at email@example.com; he cannot make personal replies.
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