no one knows.it's a mystery!
To troubleshoot inoperative daytime running lights on a 1999 Grand Marquis, check the fuse related to the DRL system, inspect the DRL module for any signs of damage or corrosion, and test the DRL relay. You may also want to examine the wiring and connectors for any issues and ensure the light bulbs are functioning properly.
It is under the dash. I believe I remember it to be the two plug module above the parking brake.
The DRL Module is located at the LH Rocker Panel left of the brake, under and just below the dash. The DRL Module and the DRL Relay are side-by-side.
To disable the Daytime Running Lights (DRL) on a 2004 Pontiac Grand Prix, you can locate the DRL fuse in the fuse box and remove it. The fuse box is typically found under the dashboard on the driver's side. Alternatively, you can turn off the DRL feature using the vehicle's headlight switch by turning it to the "off" position while the ignition is on. Make sure to check your owner’s manual for specific details regarding your model.
The daytime running lights module on a 2000 Grand Marquis is located in the passenger side engine bay. It lays between the battery and the heater blower.
A ( Daytime Running Light ) module
A DRL module controls the daylight running lights found on many newer and Canadian cars.
The drl module on chevy epica 2004 is back to the data link connector
Discovered the same problem in my Prix yesterday, something is affecting the lights sensor cause you can still turn them on manually, I'm going to check the DRL sensor wiring for shorts or something, will post again if I figure it out.
The DRL control module is located under the steering column on the left hand side!
On my 1999 Buick Regal the DRL module is located on the outside foot well behind the parking brake pedal under the carpet. My DRL has gone bad and is making the car quit.
If you mean the sensor it is on top of the dash in the middle closest to the windshield, it's a little globe looking thing.