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EricFromCT, Ford Technician
Category: Ford
Satisfied Customers: 3803
Experience:  20 years dealership exp., ASE A1-A9 L1 L2, Ford Lincoln Mercury Senior Master, Diesel Certified
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Interior lights were not fully bright when on and dimmer was

Customer Question

Interior lights were not fully bright when on and dimmer was working, then dimmer stopped and interior lights will not go off, also dash lights come on after car is parked off and doors locked for no apparent reason.
JA: Have you checked the switch?
Customer: switch works fine
JA: What is the model/year of your Ford?
Customer: 2005 crow vic
JA: Are you fixing your vehicle yourself? What have you tried so far?
Customer: unplugged and removed all the interior lights to save battery, however, battery is getting run down when dash lights come on for no apparent reason when car is parked, doors locked and off
JA: Anything else you want the mechanic to know before I connect you?
Customer: when I lock doors with remote, dash lights will go off, but I do not know for how long..
Submitted: 8 months ago.
Category: Ford
Expert:  EricFromCT replied 8 months ago.

Hi. The most common cause for this concern and any headlamp concerns is the Lighting Control Module. Some model year crown vics had a recall on it. If you give me your VIN number I can check if your vehicle has this recall.

Customer: replied 8 months ago.
LCM was replaced a couple of years ago by dealer, are you certain it is this?
could this be related to the keyless entry keypad malfunctioning, as it is not working properly now?
Expert:  EricFromCT replied 8 months ago.

I am not 100% certain, but it does control all the lighting functions. The drivers door module controls the keypad. The ddm does communicate with the LCM to work the interior lights when doors are locked/unlocked

Customer: replied 8 months ago.
What about the dash lights coming on after the car is off, doors locked and parked for a while?
Expert:  EricFromCT replied 8 months ago.

According to the wiring diagram the LCM controls the output to the radio, instrument cluster, overhead console, interior lights and climate control module. So the LCM is definitly turning those interior lights on. Now the question would have to be is it turning those on because it is faulty, or because something like a door ajar switch is telling it to turn on the lights or something along those lines.

Customer: replied 8 months ago.
When I lock the car, only one chirp is heard, so this tells me that the door-ajar switches are OK, unless they fail when in their door shut condition
Expert:  EricFromCT replied 8 months ago.

If all the inputs seem to be working that would tell the module to turn on the interior lights, or the dash lights (like the headlamp switch), then I would have to suspect that the LCM is faulty. I know it is difficult to diagnosis because you know that it is turning on the lights, but the question is is it being told to or just faulty.

Expert:  EricFromCT replied 8 months ago.

Did the dealer replace the module years ago under the recall? or did you pay to have it replaced?

Customer: replied 8 months ago.
The LCM was replaced under the recall, it took them several months to get the part
Expert:  EricFromCT replied 8 months ago.

Have you tried disconnecting the dimmer switch and/or the headlamp switch to see if the dash lights will stop coming on?

Customer: replied 8 months ago.
where are those switches?
Customer: replied 8 months ago.
I put the dimmer switch to the off position and the dash lights still come on
Expert:  EricFromCT replied 8 months ago.

The headlight switch is the switch on the left of the steering wheel where you turn on and off the headlamps. You may want to try unplugging both the switches and checking the connectors to see what happens. Perhaps the headlamp switch or dimmer switch or their connectors are faulty telling the LCM to turn on the dash lamps or interior lamps.