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Head Light Problem

A

Aussie Challenger

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Dec 30, 2012
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Location
Yarra Valley Victoria Australia
I have an unusual problem with my headlights on my '79 LRE, remember they have 4 headlights.
When vehicle arrived here in Australia the headlights worked OK but due to the fact we drive on the other side of the road I had to replace the H/L headlights, high beams are OK.
I fitted Quarts Halogen lights and fitted 100/75 globes, when lights now are on low beam the second set of original high beams lights glow dull, appears to be a ground return feed, I fitted extra grounds. Checked to see if the dip switch was feeding current which it is not. I changed lights back to originals and problem went away, fitted new lights and problem reappeared, checked terminals on new globes with originals, they are the same. Bought and fitted a second set of globes different brand, same problem.
I was going to fit relays anyway which I usually do first, so installed 3 relays running one for low beam, one for the right side high beam lights (both of them) and the third for the left side high beams. Still have the problem.
I have fitted hundreds of relays over the years, did the same to my '70 Challenger (almost the same wiring layout) with no problems but this has me stumped.
Short of cutting the wires completely out and rewiring completely, I actually ran an extra wire to the high beams on both sides to allow for the extra current, have wired in extra ground wires both sides.
Anybody had a problem like this, my usual auto electrician is out of the country for a while and other mechanic mates have never heard of this type of problem before so I have nobody I can ask?
 
Check your dimmer switch David, they like to corrode there. If you remove the drivers side fender you will see a seam that over the years the sealer hardens & shrinks allowing water to flow in & right down to the little spot where the dimmer switch is There one on the other side that does the same thing I clean them,paint them & fill them with windshield urethane
 
Thanks Bob, I have already checked the dimmer switch, not corroded, floors dry, no water leaks fortunately, vehicle spent most of its life in Arizona. There is no current coming out of the firewall on the high beam circuit when on low beam, this is what is worrying.
 
I've reread your post and I need some clairification. Here in the states, with 4 light systems. 2 are high beams and the other 2 are low beams. When on low, the latter 2 are lit and when on high, all 4 lights are lit. The usual practice on vertical lights is dims on the bottom and highs on top, while on horizontal systems the 2 insides are dim and the outside 2 brights. Do I understand that you have the 2 original high beam lights and then you added 2 dual filiment high-low lights in place of the dims?
 
To clarify, the upper headlights are the H/L the lower are high beam only. I have wired in relays for both the low beams together, the upper high beams both sides are wired to another relay and the lower high beams only are wired to another relay. As is normal the low beam turns off when the dipper switch selects high beam, therefore no current to switch the low beam circuit on but all 4 head lights on high beam are working.
My problem is that when head light is on low beam the lower set of high beams have a dull glow which tells me that there is a ground problem or a bleed across between the two. Now there is no current on the trigger wire from the dipper switch and the relays are not activated. When I put the original head lights back in there is no problem, I have tried 2 different sets of globes from different manufacturers and the pin layout is the same on all the lights.
I have also run extra ground wires and cut the loop between the upper and lower high beams. As I said I have wired hundreds of head light relays over my time as a motor mechanic, my '70 Challenger who's circuit is almost the same doesn't have this problem.
 
I don't know if it would mean anything, but when the lower set have the dull glow, you might unplug one of those lower lights and see if it affects its mate. And then you might pull the opposite one and see if it affects the opposite one. You might also pull the plug on one of the replacement bulbs and then the other to see if the lower bulbs stop glowing. If they do when you pull one but not the other, then you know the problem is with that side. And if it does, you could also swap the replacement bulbs side for side to determine if it's the bulb or wiring. If it does make a difference, just for curiosity, you could pull one of the connectors off half way to see if the problem ceases. Makes me wonder if maybe one of the plastic connectors is slightly damaged and maybe the tangs on the new bulbs are just a bit longer and are shoving the metal spades into contact. Also, does the high beam indicator light glow any when the lights are supposed to be on low beam? If so, then you would know for sure that juice was backfeeding somewhere. It would make one think the terminals on the replacement bulbs were reversed, but I don't see how. And I know up here that the terminals for both old style tungsten and quartz bulbs are the same because I've swapped them on my bikes.

I don't know if I've been any help, but it's just a bunch of crazy ideas that I would try in an effort to narrow down the problem to a more specific side, bulb or connector. Good luck, I know how difficult electrical gremlins can be to trace down. Like the time my bike wouldn't start. I finally traced it down to the kill switch on the ignition. The crazy thing is, with a multimeter the switch checked out perfectly every time, but when the ignition was turned on, the switch wouldn't pass any juice at all. Being part of the handlebar switches, I finally just wired around it.
 
Sounds like you are using the high beam lights as a ground for the low beam lights. In the US we wire four lights as such. From back side of high beam light , left side ground, center high beam, right side low beam. Low beam light, left side ground and right side low beam. Both sides are wired this way.
 
bikinkawboy, thanks for those comments and suggestions, terminals are all the same length and yes I have removed one side at a time to see if that made any difference and the high beam indicator doesn't show at all and I will be attending to that when I have the speedo removed soon.

7mopar, yes I was thinking along the lines of feed back through the high beam so ran new extra grounds from both the upper H/L and the lower high beams but no difference. Originally I didn't fit the relays first which is normal for me so when I did install I thought I had any feed back problems licked because of the relays but it didn't do a thing.

My next thing will be to just run new wires straight from the relays to the head lights, if that doesn't work.........
 
Aussie Challenger, I would attempted to attach the wiring diagram for a 4 headlight system. If I could only figure out how
 
7mopar said:
Aussie Challenger, I would attempted to attach the wiring diagram for a 4 headlight system. If I could only figure out how
Click to expand...
I have already downloaded the complete Dodge D150 for 1979, the circuit matches up with what I already have found out by tracing the circuit in the truck.
As soon as I get a few hours I will just run a new set of wires directly to the headlights and by-pass the original wires past the relays to the headlights, if there is still a problem........
The circuit up too the relays is working fine, but if running seperate wires it doesn't really tell me the problem and why it goes away when the original low powered headlights don't have a problem.
 
I believe the problem is your original idea of how these lights work in there original arrangement. There is only 1 high/low beam light (3 wires) with 1 low beam light(2 wires) per side of vehicle. The lights with 2 wires are continually low beam regardless if the high beam indicator light is on. If you replace the low beam light with a high/low beam light a jumper wire will have to be installed from the high beam terminal (center wire) on the original high/low beam light to the new high/low beam light you installed. Regardless of which bulb you use when looking at the back side of the bulb the terminal on the left side is ground. By the way in the Us all high beams have to be off when on low beam setting. Hope this resolves your problem.
 
7mopar said:
I believe the problem is your original idea of how these lights work in there original arrangement. There is only 1 high/low beam light (3 wires) with 1 low beam light(2 wires) per side of vehicle. The lights with 2 wires are continually low beam regardless if the high beam indicator light is on. If you replace the low beam light with a high/low beam light a jumper wire will have to be installed from the high beam terminal (center wire) on the original high/low beam light to the new high/low beam light you installed. Regardless of which bulb you use when looking at the back side of the bulb the terminal on the left side is ground. By the way in the Us all high beams have to be off when on low beam setting. Hope this resolves your problem.
Click to expand...
No the original upper H/L headlight is dual filament, hence on low beam the uppers headlights are on and on high beam both the upper and lower headlights light up but the low beam filament turns off in the upper beam as the high beam turns on, this is normal and standard both here in Australia, New Zealand, Britain or America and most countries. I have converted many American cars over the years and as I have mentioned my '70 Challenger has basically the same wiring loom except the headlights are side by side instead of on top of one another.
 
I stand corrected on bulb wiring ground left,low beam middle and right high beam. But the big question if these light work the same in most countries why the required change just because you drive on the other side of the road. Also I presume you have checked the battery to body ground. Adding the other high beam may be to much for it. Electricity follows the path of least resistance and may be feeding the other filament instead going directly to ground.
 
As we drive on the other side (left) of the road the low beams dip the opposite way to yours, your lights would dazzle on coming traffic over here and likewise our low beams would dazzle your on coming drivers. I have mentioned what I have done with the grounds, it is not that this is the first time I have done this. I have been working in the auto repair industry for over 40 years now and this problem appears to be a wiring problem so I will just have to run new wires from the relays directly to the lights and by-pass the rest of the wires, it is a bit of a nuisance as I have taped the extra wires back into the existing loom to make it look neat.
 
I know how electrical gremlins can have you pulling your hair out, My "big" bike, an '84 6 cylinder Kawasaki Voyager is a dresser and has about every kind of electrical doo-dad imaginable on it. Electric air compressor for pumping up the air shocks, electric compass, one of the first electrical ignition advance, transistorized ignition, lights, electronic turn signal canceler, bells, whistles and so on. When everything is working right, it's great. When not, it's a nightmare. The fairing is plumb full of wires, under the tank are more wires and under the seat is another rat's nest of wires and electrical components. The Japanese designers did a great job of stuffing a lot of stuff into a small place, but when it comes to tracing down electrical issues, what a headache! There are countless wire connectors, many of which are very prone to corrosion, leading to melted down connectors. At least with our trucks, we have some working room unlike my bike. So about the only help I can give you is moral support in knowing how frustrating and time consuming such problems can be. And the really frustrating ones are like yours, where they work sometimes but not others. The plain old dead ones are easier to find and fix. Good luck and if you find the problem, I'd like to hear what it is.
 
Thanks bikinkawboy, I don't have much hair to pull out these days, I will definitely post my results, thanks for the encouragement problems like these don't happen too often and I don't need it at the moment.
 
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