Just did the headlight relay mod..

[Boltgun]

And wow, what a difference.

I cheated and used the kit from LMC truck, it just wasn't worth my time to gather up the pieces, solder, heat shrink, measure, cut....to save $5. The kit is from the PRC, no surprise there, but seems to be decent quality. There were a few connections I would have liked to have seen heat shrink on, and I wish the chaff protection wasn't bright yellow, but overall a good kit.

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One note, while it looks like a "universal" kit, the wires were the correct length on everything, assuming your tapping power off of the starter relay and grounding to the core support.

Results:
Old high beam

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New high beam

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Old low beam

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New low beam

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I'll get pics of the install if anyone wants them, but it really is plug and play. Like I did it while my 6mo was taking a nap, and had time left over. For the cost of half a tank of fuel, you can't afford not to do this.

 

[yARIC008]

Cool, looks like it'll work well. The only thing I don't like about this mod is the additional heat that is generated. If your headlight lenses were dull and dusty looking before this will accelerate that.

 

[Ruger_556]

All a relay harness does is eliminate any voltage drop in the factory wiring. Any additional heat is just the headlights working the factory intended...

 

[FORDF250HDXLT]

Cool, looks like it'll work well. The only thing I don't like about this mod is the additional heat that is generated. If your headlight lenses were dull and dusty looking before this will accelerate that.

this kinda goes hand in hand with new lenses though imho.these are old trucks with no doubt,very unsafe oem headlight lenses if they haven't been replaced yet.
i did the relay mod w/ new lenses on my 250 and i just picked up the relays/fuse holders (i prefer to build my own harness) today with.....you guessed it,new headlight lenses in the mail for the f450.

it's a good idea to inspect your headlight switch harness while doing this mod as well.it may be partially burnt up already and a good time to just replace it.lucky for me,iv got to go in there to replace some gauge bulbs anyway.i think it was doorman,sold at AZ that makes the new hl switch plugs.the new one and the hl switch won't be taking the big draw anymore so it'll never heat up and burn again with the relays.

 

[Lithgow]

Thanks for the info. This is on my list too. I recently replaced my headlight switch and it had a burned looking area as well.

 

[ZWilson07]

this kinda goes hand in hand with new lenses though imho.these are old trucks with no doubt,very unsafe oem headlight lenses if they haven't been replaced yet.
i did the relay mod w/ new lenses on my 250 and i just picked up the relays/fuse holders (i prefer to build my own harness) today with.....you guessed it,new headlight lenses in the mail for the f450.

it's a good idea to inspect your headlight switch harness while doing this mod as well.it may be partially burnt up already and a good time to just replace it.lucky for me,iv got to go in there to replace some gauge bulbs anyway.i think it was doorman,sold at AZ that makes the new hl switch plugs.the new one and the hl switch won't be taking the big draw anymore so it'll never heat up and burn again with the relays.

Is changing out the factory headlight lenses a good idea for bricknose as well or only an obs thing?

Any good place to go through to get them?

 

[FORDF250HDXLT]

well you can go with just factory replacements if you don't care for/want the clear styling.just as long as they get replaced if they're original and yellowed.you can only clean the old things so much.once you change them,that's when you realize you've got modern white lights like any other safe car on the road again.

 

[Boltgun]

Good call on the headlight switch, I checked mine last week while chasing down some other electrical gremlins and it was in surprisingly good shape. New lenses will be on the agenda if these don't clean up.

 

[idi_econoline]

FYI, Boltgun: Earlier threads have spoken unkindly about the relays in the LMC kit. They're not the best choice, and have been susceptible to moisture.

I have the same kit, but am waiting to upgrade it with better relays, after I deal with a chuffing exhaust valve. I have a Crown Vic pair, as mentioned in this thread:

http://www.oilburners.net/forums/showthread.php?60372-lmc-headlight-relay-harness

Of course, I'll need about an hour with my meter to figure out the wiring on the Crown Vic unit.

 

[Bashby]

I saw a relay for something once that was mounted upside down and it was full of water. I always make sure to mount them with the wires facing down so they drain.

 

[Ruger_556]

They make weather sealed relays... I used one to trigger my fog lights with the low beams GM has the same problem with headlight switches burning up so I used the factory wiring to trigger the relay and the switched side is battery powered while using the original harness up to the headlights.

 

[Boltgun]

I sorta figured the relays were junk, I was planning on just upgrading to bosh units later, but the crown Vic setup looks slick. Off to the pull-a-part...

 

[kc0stp]

well you can go with just factory replacements if you don't care for/want the clear styling.just as long as they get replaced if they're original and yellowed.you can only clean the old things so much.once you change them,that's when you realize you've got modern white lights like any other safe car on the road again.

For a bricknose all that is available is factory replacements unfortunately.

 

[LCAM-01XA]

Of course, I'll need about an hour with my meter to figure out the wiring on the Crown Vic unit.

Or you can just ask which wire does what First you should verify your LMC harness is wired up as follows:

solid white = low beams relay trigger
solid brown = high beams relay trigger
blue/white = relays ground (for both together)
solid yellow = low beams power
solid blue = high beams power
solid red and red/white = relays battery power

Now go ahead and chop off the two LMC relay connectors and discard them. Keep the other 3 connectors for headlights and factory harness. Discard the solid red and red/white LMC relay power wires. Discard the short piece of blue/white wire that runs between the two relay connectors. You should now be left with one long blue/white wire & one white wire & one brown wire (all three of these hooked up to the same connector on the other end), then two yellow wires, and finally two solid blue wires. And this is how you connect the Crown Vic box to them:

red/black Crown Vic wire -> extend, fuse for high beams, and hook up to battery
solid yellow Crown Vic wire-> extend, fuse for low beams, and hook up to battery
solid black & green/black Crown Vic wires -> twist together and connect both to single blue/white LMC wire
orange/lightblue Crown Vic wire -> connect to both solid blue LMC wires together
yellow/darkblue Crown Vic wire -> connect to both solid yellow LMC wires together
red/silverdash Crown Vic wire -> connect to solid brown LMC wire
red/lightblue Crown Vic wire -> connect to solid white LMC wire

And that should about do it. Do keep in mind this was all sorted out for an '80-'86 truck with sealed beams, but AFAIK all IDI trucks have the same factory color codes on their headlights harness (red/black is low, green/black is high beams) so you should be able to easily adapt the general principle to your exact truck. And ya'll can go ahead and thanks Mojavewolfpup for working with me to figure it out, he was kind enough to provide detailed pics of both an open Crown Vic box (as all of mine are installed and VERY inaccessible) and the LMC harness that is correct for his "slantnose" truck.

As far as fuses go, those depend on your headlights. A pair of standard 45/65 sealed beams will pull around 8 amps on low and 11 on high, so if you fuse them at 15 amps low and 20 amps high I think you will be giving them some wiggle room without going too loose, and thus will neither blow fuses all the time nor burn wires should something short-circuit.

 

[88beast]

now get new lenses and better bulbs, my low beams are like most high beams and my high beams with the off road lights (kc) light everything up like day