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Ask Kenny Z. Your Own Question
Kenny Z.
Kenny Z., Ford Senior Master Tech
Category: Ford
Satisfied Customers: 5381
Experience:  Auto Trans, Drivability and Electrical Specialist
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Turn the car on and my headlites come on.. even with the

Customer Question

turn the car on and my headlites come on.. even with the inside switch disconected
JA: What is the model/year of your Ford?
Customer: 1999 winstar sc???
JA: Are you hoping to fix this yourself? What have you tried so far?
Customer: yes, looking for bad ground or schaffed wires
JA: Have you checked all the fuses? Do you have a wiring diagram?
Customer: yes all working
JA: Anything else you think the mechanic should know?
Customer: it's HOT
Submitted: 1 year ago.
Category: Ford
Customer: replied 1 year ago.
Alternator is working but the battery still runs down while driving. 2 new batteries within 2 days...under warranty. I have not yet checked any relay fuses tho.
Expert:  Kenny Z. replied 1 year ago.

Hello, my name is***** and thanks for your question.

Is the vehicle equipped with auto lamps?

Is the vehicle equipped with daytime running lamps?

Customer: replied 1 year ago.
auto lamps...??? the lite switch can be turned to the left to have the lites come on and auto off, but I don't use it. Plus I disconnected the lite switch and lites still come on. And no running lights on car.
Expert:  Kenny Z. replied 1 year ago.

Ok thanks. Just FYI, the lighting control system on this vehicle is the most complex and most difficult to diagnose system ford ever designed, especially if you don't have a ford scan tool. I'm not trying to push you off. Here is how this system works.

The headlamps are controlled by the front electronic module (FEM) and instrument cluster module (IC). The headlamp and multifunction switches are hardwired to the instrument cluster. When the headlamp switch is in any position, the instrument cluster module will send a command to the FEM through the SCP communication network. The FEM will process this information and output the appropriate command to the headlamps, which are hardwired to the FEM. This is the same for the high beams and flash-to-pass functions, which are controlled by the multifunction switch. That being said the concern you have can be caused by several issues. The IC could be corrupt and sending false on signals to the FEM. The FEM can be corrupt and be energizing the headlamps without being commanded. There could be a wiring issue between the headlamp switch and the IC. Both of these modules have on board diagnostics which can be accessed with a dealer level scan tool. They also have on board monitoring capabilities which can be accesses with a dealer level scan tool. Inputs and commands can be monitored as well as network activity between the modules. The headlamps are powered continuously, the FEM controls them by adding or removing ground. So you know the power side is OK, and you have a control issue which I cannot even begin to lead you in diagnosis with out a dealer level scan tool. I usually get negative ratings from answers like this, but I wanted to at least let you know what is involved in this system and what you are up against.

Customer: replied 1 year ago.
can I take the fuse/fuses out to just run during the day til I get my ssd check? Kind of low on money right now. or just take the bulbs out. And is this what is running my battery down. The problem you described.
Expert:  Kenny Z. replied 1 year ago.
disconnecting the fuses should be fine I don't see how that would cause your battery to go dead If the alternator is charging
Expert:  Kenny Z. replied 1 year ago.

Hello again,

If you need further assistance please feel free to reply and we can continue. Otherwise please take a moment to rate my answer as you see fit. After rating, the thread is still available should you need further assistance. Experts are not compensated without a positive rating. Providing a rating does not close the question, you can reply or ask additional questions without incurring further charges.


Kenny Z