Maverickdude

I have a 2005 Vrown Vic P71 with low beam headlights intermittently not turning on, or turning off while on. I've determiined that the problem is most likely one of the 4 relays in the upper PCB of the Lighting control module. When my headlights do not turn on, a tap on the module will turn them on. However, I find it odd that I hear the relay kick in when I tap on the module. If the relay were bad, I would suspect poor relay contacts, not a stuck relay contact mechanism. The solder joints on PCB look good. I don't think the problem is a cold solder joint. If anyone could describe which relay is for the low beams or can provide a pic pointing out the correct relay, that would be great!

jwko

Moved to the CV section.

CatSkinner

Often times, when a coil gets old, it's magnetic strength weakens due to heat build up increasing the resistance. Tapping it agitates it enough for the switch to overcome friction and throw.

__________________
Prius repellant, just add gas.

Bert

The lighting control module has been known to have that problem.

__________________
Bert

no_common_sens

I never figured out which ones were which while I was still rebuilding them but the PCB should tell you which relay burned up. Look at the circuits coming from and going to the relays on the backside of the board. Whichever ones that show some browning to them should be connected to the relay that failed. If nothing else, just replace all four of them anyway, They're cheap and available at mouser.com. Or you can do an external relay mod. crownvic dot net probably has a million threads pertaining to the external mod if you're interested.

Jeff Collision

It could be your LCM(lighting control module) located under the dash above your right foot, or the multi function switch could also be a culprit.