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hello all,
I have a 2001 Lincoln towncar with an issue with the headlights on the normal beam. when its turned on only one is on and the other isn’t, the light itself is working as I did swap and check that its working..
other electricians checked it and said it was a problem either in the wiring harness or the LCM and more are going towards the LCM..
I was just thinking as a simple fix, can I convert the lights from LCM controlled and powered to direct battery powered with a relay and the actual wire going to the working headlight to control that relay??
would this work?
one more thing, can anyone share the headlight harness routing diagram?
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If LCM directly controls headlights (I couldn’t find wiring diagram) and is faulty.
There is couple of different methods on going around this problem.
-You can connect relay coil in parallel with working headlight to power the non-working one. You should use relay with diode to protect LCM (really only needed if headlight bulb burns out (if its halogen bulb)).
-You can connect relay in place of working headlight to power both headlights. You should use relay with diode to protect LCM.
-You can completely bypass LCM and connect headlight switch directly to relay that powers headlights. If this isn’t connected to LCM you don’t even need diode to protect LCM.thanks for the info, what i am planning to do is actually is connecting a relay in place of the working headlight to power both headlights.. but i need to ask about the following
why should i have a diode?? if i use the working light to activate the control of the relay to power the lights from the battery then there should be no power going back to the lcm
LCM headlight wire –> (diode) –> (ping 86) Relay control (ping 85) –> ground
is that correct?
would there be a problem if the LCM goes to the ground as the above?
That’s the second option. Diode needs to be parallel to relay coil to protect ECM from inductive spike that relay will cause.
First you connect diode like http://www.12voltplanet.co.uk/user/Relay_with_diode_across_coil.png and then connect LCM headlight wire –> (ping 86) Relay control (ping 85) –> groundBefore you get in too deep with this, check the fuses. Each headlight circuit has it’s own fuse. If the one for the headlight that’s out is blown, it won’t light. More info here.
http://www.ericthecarguy.com/faq/solving-automotive-electrical-problems
Keep us posted.
[quote=”aknight_sa” post=89362]hello all,
I have a 2001 Lincoln towncar with an issue with the headlights on the normal beam. when its turned on only one is on and the other isn’t, the light itself is working as I did swap and check that its working..
other electricians checked it and said it was a problem either in the wiring harness or the LCM and more are going towards the LCM..
I was just thinking as a simple fix, can I convert the lights from LCM controlled and powered to direct battery powered with a relay and the actual wire going to the working headlight to control that relay??
You can go to bbbindustries.com and get the wiring diagram
would this work?
one more thing, can anyone share the headlight harness routing diagram?[/quote]
[quote=”valde” post=89819]That’s the second option. Diode needs to be parallel to relay coil to protect ECM from inductive spike that relay will cause.
First you connect diode like http://www.12voltplanet.co.uk/user/Relay_with_diode_across_coil.png and then connect LCM headlight wire –> (ping 86) Relay control (ping 85) –> ground[/quote]is the diode part of the relay??
You may be able to find relay with diode or just use separate diode. It may work without it but not using one is common reason why cars with electrical additions tend to have electrical problems.
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