Thread: LED help

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My old hot rod has led lights on it and there not very bright.if you put 12 volts to them out of the car they seem really bright.been told they might have some sort of resester in line somewhere ,how would i check that? ther is only one wire that runs to each tail light to run tail,turn,stop,all work properly but to dim to see in daytime or when car is close at night.any help would be aprisiated.

check your grounds...
and paint the inside of the tail light housing white or silver...joe

Originally Posted by plumpurpleplym

ther is only one wire that runs to each tail light to run tail,turn,stop,all work properly but to dim to see in daytime or when car is close at night.

Are you saying there is only one wire to each lamp, and that one wire supports tail, turn and stop? If you have only one wire (plus a ground wire or a ground terminal where you hook a ground wire) then I would say your tail lights are not made for the brake/turn function. There would have to be a second hot wire to increase the intensity, like the second filament on a 1357 incandescent - two hots, one ground to the case. A single filament bulb could work for tail/turn, but your turn function would have to interrupt the ground to make the light go out intermittently. At least that's how it seems to me.

the grounds are never interrupted in lighting systems---only for some computer controlled things where they need to reduce the amperage to reduce heat in the computer

Originally Posted by jerry clayton

the grounds are never interrupted in lighting systems---only for some computer controlled things where they need to reduce the amperage to reduce heat in the computer

Most dome lights have the ground wire running to the door switches, and in parallel to the headlight switch on the old pull on, rotary dimmer for dash lights, and all the way left or right for dome on style switch. Other circuit applications put the switch in the ground lead so that the switch can have less current capacity and be less bulky.

OK roger---we agree on less current thru the switch---

yes the dome lights are operated by a constant feed and grounding door switches---

the op was referring to a tail lite on a 36 plymouth--on this car originally was 6 volt and maybe pos gr but most likely now is 12 v neg gr---originally would not of had turn signals, now has led, and is inproperly wired-----in order to save material, light systems will be grounded at the mounting point with only the feed wires going to them---

Of course this creates a problem withfiberglass cars and boats

Originally Posted by jerry clayton

OK roger---we agree on less current thru the switch---

yes the dome lights are operated by a constant feed and grounding door switches---

the op was referring to a tail lite on a 36 plymouth--on this car originally was 6 volt and maybe pos gr but most likely now is 12 v neg gr---originally would not of had turn signals, now has led, and is inproperly wired-----in order to save material, light systems will be grounded at the mounting point with only the feed wires going to them---

Of course this creates a problem withfiberglass cars and boats

Jerry, I was simply trying to point out that plumpurpleplym had described a system that can't work, and you'll note that I asked him to clarify his statement. You have made several assumptions regarding his car - original wiring, likely conversion to 12v neg, no added wiring... but you are probably 100% right on everything stated so I'll not add any further confusion to the thread.

OK guys this a steel car.12 volt system.Nothing is orig.about wiring.one wire to mounting bolt-ground.one wire to lamp can that runs tail, turn, brake.there are 13 lamps inside each housing,with several resisters?I guess, between them.I dont get how it works but it works,just to dim.

I would say that if its too dim that it doesn't work

And a tail, turn, stop lite uses a bulb(or two bulbs) with 2 different candle power that creates the tail, turn, stop function which requires a feed to the tail portion that will be fired directly from the headlight switch and a stop/turn function that will be powered via turn signal/brake lite switches-----there will be 3 wires, of which one is a grd and if yours is just grounded thru the housing to the STEEL fender---a rubber gromment around the lite housing will prevent the ground and poor continuity between separate fenders(old cars) body and frames back to the battery will prevent proper electrical flow

Start with the maker of the lites and see if they have suggestions. Is your whole assembly a custom or just the bulb? I recently made and installed LED's in my bed rails using an 1157 socket and the LED version of the bulb. There were grounds coming out of each tail light (total of three wires per side coming out of the lite) two function wires one ground.

I will check on volts , and try runing groud to batt. but there will still be only 1 wire to make all functions work , its over my head but it does work [ even if dim] with 1 wire. as for light boxes,thy are custom made,no manufacturers stamp.If any one buildes a car,and dosn't make a bible to go with it I really do not get it.I bought this car at a leake auction about a year ago,no book of any kind ,so every t hing I get into is a nightmare.But I love every min.