2 filiment bulb help
Thread Starter
|
FTE Chapter Leader
Joined: May 2001
Posts: 3,322
Likes: 20
From: Rhode Island
2 filiment bulb help
ok... excuse my ignoracne... its been a long day...
two filiment bulbs... Im currently re-wiring a street rod.... and the tail lights of the truck have three wires going into it... two of the wires come together in the harness...
Mind you im having problems with the wiring harness to begin with ... but how do these bulbs actually work... im lost ... like I said... long day...
simple wiring diagrams... would be helpful... plus a describtion ...
thanks
two filiment bulbs... Im currently re-wiring a street rod.... and the tail lights of the truck have three wires going into it... two of the wires come together in the harness...
Mind you im having problems with the wiring harness to begin with ... but how do these bulbs actually work... im lost ... like I said... long day...
simple wiring diagrams... would be helpful... plus a describtion ...
thanks
Moderator
Joined: Jan 2001
Posts: 56,984
Likes: 2,738
From: Virginia
The most common two filament bulbs used are #1157. There are a few others.
The bulb itself has 3 connections. Two of them are on the base of the bulb, and look like little round silver spots. The other connection is the brass part of the bulb itself. This brass part is the common ground for the two filaments(the two round silver spots).
So the brass part of the bulb gets grounded to the frame, or if you have a fiberglass body, gets tied to the seperate grounding system of the car. If you do not know which wire is ground, take an ohmmeter and in rx1 scale, and see which wire has continuity to the little tang on the side of the socket that touches the brass part of the bulb.
Then you have the other two wires. Get a battery charger or something, and hook the negative of the battery charger to ground, and hook the positive lead to one of the remaining two wires. Try both one at a time. One wire will give a bright light, and one will give a dimmer light.
The wire that gives out the dim light goes to the running lights. This will be a common wire that will also go to the other taillight running light, and also go to the license plate lights, and any other running lights you have.
The brighter light wire is the brake/turn light. This will be a seperate circuit that comes from the turnsignal switch. You will have seperate left and right wires going from the turnsignal switch to each rear turn/brake bright filament wire.
The turnsignal switch combines the brake and the turnsignal functions together. If you want a simple seperate switch for the turnsignals , and still combine the brake light wires to the same filaments, I have a trick for that too.
The bulb itself has 3 connections. Two of them are on the base of the bulb, and look like little round silver spots. The other connection is the brass part of the bulb itself. This brass part is the common ground for the two filaments(the two round silver spots).
So the brass part of the bulb gets grounded to the frame, or if you have a fiberglass body, gets tied to the seperate grounding system of the car. If you do not know which wire is ground, take an ohmmeter and in rx1 scale, and see which wire has continuity to the little tang on the side of the socket that touches the brass part of the bulb.
Then you have the other two wires. Get a battery charger or something, and hook the negative of the battery charger to ground, and hook the positive lead to one of the remaining two wires. Try both one at a time. One wire will give a bright light, and one will give a dimmer light.
The wire that gives out the dim light goes to the running lights. This will be a common wire that will also go to the other taillight running light, and also go to the license plate lights, and any other running lights you have.
The brighter light wire is the brake/turn light. This will be a seperate circuit that comes from the turnsignal switch. You will have seperate left and right wires going from the turnsignal switch to each rear turn/brake bright filament wire.
The turnsignal switch combines the brake and the turnsignal functions together. If you want a simple seperate switch for the turnsignals , and still combine the brake light wires to the same filaments, I have a trick for that too.
