Okay, on an 1157 bulb , you have one pin lower on the bulb and one that is higher up on the bulb . The bulb only fits in the socket one way, which pin would lead to the brake light part of the bulb , the lower or the higher pin? I know its kind of a stupid question, but i can't find any info on this. When i use a 12 volt battery, no matter what i do, i can only light up the top filament, but not the lower, so i can't figure out which wire to connect too for brake/turn and taillight........
1157 bulb and socket question
- Thread starter hotwheels
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dmw56
Busted and Rusted on Route 66
The index pins have nothing to do with lighting up the bulb. They just position it correctly. You will have 3 wires going to the bulb. The housing the pins are attached to is the ground. A wire from your brakes/turn signal goes to the lead (Pb) terminal on the bottom which illuminates the larger brighter filament. The taillight wire goes to the lead (Pb) terminal on the bottom which illuminates the smaller dimmer filament.
sgtpontiac
Older, Wiser and Still Buildin'
I've seen people force them in the socket...
the running light is the bright one and the brake light is the dim one, can be done but you have to be a Knucklehead to force it that way....lol
the running light is the bright one and the brake light is the dim one, can be done but you have to be a Knucklehead to force it that way....lol
The 1157 socket i have only has two wires and they are both black....So i am trying to figure out which black wire i need to hook my taillight wire too and which black wire i need to hook up to for my brake/turnsignal filament....from the image i attached, i thought it was trying to show which filament aligned with the turn/brake and taillight.
sgtpontiac
Older, Wiser and Still Buildin'
simple enough.....
power one of the wires with the lamp socket grounded...if it's bright you have the brake turn signal wire.. mark it... the other is the running / tail light....
Bob's your uncle!
power one of the wires with the lamp socket grounded...if it's bright you have the brake turn signal wire.. mark it... the other is the running / tail light....
Bob's your uncle!
I tried that.......I can take the two wires from the socket, connect one wire to the neg, and one to the positive and it lights up the top filament, switch the wires on the battery and it again, lights up the top filament........
I was thinking from this image that maybe the alignment of the pins would show which was supposed to be brake/turn and tail............
I was thinking from this image that maybe the alignment of the pins would show which was supposed to be brake/turn and tail............
Attachments
bob w
Still crazy after all these years!
The fiber disc with the two contacts is oriented by a small tab that rides in a slot in the metal socket. They can be forced out of position if the tab is worn or if the socket is of poor quality (from a foreign land).
You can check the bulb with a battery by running a wire from the negative terminal to the body of the bulb. Another wire from the positive terminal can be touched on the bulb contacts one at a time. Obviously the brighter one is the brake light filament. Note which pin is by that terminal.
You can check the bulb with a battery by running a wire from the negative terminal to the body of the bulb. Another wire from the positive terminal can be touched on the bulb contacts one at a time. Obviously the brighter one is the brake light filament. Note which pin is by that terminal.
I tried that bob and still can only light the upper filament, no matter which bump i touch on the bottom of the bulb.......these bulbs are brand new, so i am lost.....maybe i will buy a better value bulb and try this again. I purchased cheap ass lights.......
sgtpontiac
Older, Wiser and Still Buildin'
Ok, maybe I missed something....
Your socket...diffenately a 1157 type... has two wires.... if that is the case, the socket itself is ground and the two wires are hot.... one is fed from the tail light circuit other other from the brake lite/turn signal switch.... you have to ground the case / socket / housing that the bulb goes in and power the wires....
Your socket...diffenately a 1157 type... has two wires.... if that is the case, the socket itself is ground and the two wires are hot.... one is fed from the tail light circuit other other from the brake lite/turn signal switch.... you have to ground the case / socket / housing that the bulb goes in and power the wires....
dmw56
Busted and Rusted on Route 66
Sounds like a defective bulb.
Correction on my post 2 wires to socket. But I have had to run a ground wire to the frame in some case because the taillight housing didn't ground.
Correction on my post 2 wires to socket. But I have had to run a ground wire to the frame in some case because the taillight housing didn't ground.
railroad
Well-known member
The two lead bumps on the bottom are both for hot wires, one is not the ground. the brass case is the ground. Touch the ground wire to the brass part of the base and a hot wire to either lead bump on the bottom. Did I miss something?
sgtpontiac
Older, Wiser and Still Buildin'
don't think we missed anything....
I think they were expecting the one wire to ground and the other to run the filiments...anyway.... they do need to ground the socket and power the wires to determine which wire feeds the brake lite and the other the tail lights....I think we are on the same sheet of music...LOL
I think they were expecting the one wire to ground and the other to run the filiments...anyway.... they do need to ground the socket and power the wires to determine which wire feeds the brake lite and the other the tail lights....I think we are on the same sheet of music...LOL
sneakysnake
"There’s nothing new in originality"
Does your socket have two terminals in the bottom? two wires one for each and the base will be the ground
LOWANDRATY
Well-known member
lights
You would be surprised how many times it's a bad bulb, I get cars in all the time with the complaint of all the parking light come on when I hit my brake pedal, the first thing I ask is, what bulb did you just change, they look at me with amazement and say how did you know I put a new bulb in, then they show me what bulb was installed, and it is always either they put the wrong bulb in and it is contacting both contacts at one time, or the cheep store bulbs both fillaments are touching togeather inside the bulb. these cheep parts cause more trouble than they are worth.
You would be surprised how many times it's a bad bulb, I get cars in all the time with the complaint of all the parking light come on when I hit my brake pedal, the first thing I ask is, what bulb did you just change, they look at me with amazement and say how did you know I put a new bulb in, then they show me what bulb was installed, and it is always either they put the wrong bulb in and it is contacting both contacts at one time, or the cheep store bulbs both fillaments are touching togeather inside the bulb. these cheep parts cause more trouble than they are worth.
TexA
Well-known member
With a VOLT-OHM-METER set to read Ohms/Resistance (on any scale)
you can test the filaments in the bulb by putting one test lead on the BASE and the other test lead on the Contact-Point on the insulated portion of the bulb.
If both filaments are intact,
the METER will indicate a DIRECT SHORT on each contact
& the bulbs are GOOD........
you can test the filaments in the bulb by putting one test lead on the BASE and the other test lead on the Contact-Point on the insulated portion of the bulb.
If both filaments are intact,
the METER will indicate a DIRECT SHORT on each contact
& the bulbs are GOOD........
