I have 2004 Mercury Marauder 4.6 V8 32V with an electrical problem that I have not been able to solve. Briefly, I spun a main bearing and had my engine rebuilt. Once the shop got everything back together, the engine ran fine (still does). But the headlights come on and off randomly, the horn goes on and off randomly, sometimes the horn goes on and never goes off, even after shutting of the engine and removing the key. The turn signals sometimes don't work at all. Very strange stuff.

Now.... I know this sounds like a bad LCM. The problem is, it's on its third LCM and still does all these weird things. I can install a brand new, from the dealer LCM, start the engine and 30 seconds later it’s the lightshow I've described. The LCM has three cable bundles that plug into it. I've check the ground on all the lines that should be ground and they are solid ground (no floating grounds). I've check the power on all the lines that should have power. Nothing over 14.5 volts. So the car has literally been sitting in my garage for about 4 years since I've basically given up.

Any thoughts on how to resolve these problems?

  • Hi, welcome to the site :) Which engine do you have? – George Mar 3 '19 at 22:11
  • Ford Modular 4.6L V8, 32 valve. – mbmast Mar 5 '19 at 21:10

Headlites, horn, turn signals, all the stuff alarm installers monkey with when they do an install. They install them behind the lower left side of the dash close to the headlight switch. Look for non-OEM wiring job and those crimp-on wire splices.

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