Headlights will turn off unexpectdly during operation. seems to be an intermittent open in the circuit. I have checked and cleaned the batt cables and checked for bad ground and burned out fuses. problem is not isolated to the automatic daylight sensor system because when headlights are nonfunctional in auto mode will also not work in manual mode
problem with the headlights on 2005 Mercury Grand Marquis
by mparish in El Centro, CA on January 13, 2010
ANSWER by Visitor , April 09, 2010
Is this a corroded conection on right side of car?
ANSWER by dandd , January 14, 2010
Need to get the wiring schematics and head light system inspection information I would go here: http://bit.ly/alldata_repair_manuals
ANSWER by Justinsmith7534 , June 21, 2015
In my 2000 Mercury Grand Marquis my lights shut off when I'm driving
ANSWER by Visitor , December 16, 2010
It is definetly your Headlight controll module. I had the same problem with my 05 grand marquis, go on Ebay and get one like i did they only cost $ 75 and come with a liftime warranty. This is going to fix your problem permanetly.