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No headlights on 2004 Mercury Grand Marquis

  

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The headlights will not turn on and the factory bypass has been installed for the LCM.  I can hold the turn stalk in the bright position and they will stay on as long as I hold it.  Push the stalk in the high beam position it will not turn on only when you pull and hold it.  I did not see a relay for the headlights only individual fuses for the left and right headlights.  When I replaced the turn signal stalk, nothing changed.  The turn signal works, but the light on the dash show both the turn signal and the hazard light, even though they appear to work normally.  DO I have to replace the LCM even though they did the factory recommended bypass?  I am not sure where else to look.

Randy


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Look in your owner's manual for the headlight relay, or search online for your headlight relay, specifying the factory LCM modification. That should bring up something. Typically, they don't run the full 12 volts directly through the firewall and into the headlight switch. There's almost always a relay that runs based on the switch position so the two circuits can be independent of each other, with the 12 volt side being in the engine bay and the 5 volt relay running into the switch itself. 

It most likely won't apply to your car, but some relays can be in pretty awkward places. My '79 Pontiac Catalina's low beam headlights went out a couple years ago. The high beams were still fine. I got off the highway and called my wife to come and get me instead of blinding people with my high beams. I got the car the next day. The relay was inside the car, on top of the steering column, underneath the dashboard. I had to partly detach the steering wheel and use my slim hands to get at that relay.


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