Turn signal issue
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Teching In
Joined: Jul 2007
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Turn signal issue Having a problem with the rear outer right turn signal tail-light bulb. When the turn signal is flipped on, only the filament for the marker light it flashing, thus, it is not as bright as the inner turn signal light bulb that lights on the correct filament. Anyone have any ideas why this might be like this and how to fix it?
The wiring at the rear of the car looks correct, but I'm wondering if something might be wrong with how it's wired under the dash?
The wiring at the rear of the car looks correct, but I'm wondering if something might be wrong with how it's wired under the dash?
Joined: Nov 2003
Posts: 11,330
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From: Jacksonville, FL (originally from Toronto Canada)
You don't mention what kind of car but I'm going to assume Firebird since Camaros have a separate amber turn signal that has only a single bulb (although it could be an LT1 Camaro).
The problem is definitely not under the dash. The bulbs are not wired separately from the front of the car so if any bulb works there is nothing wrong with the wiring from the dash to the back of the car.
Again, assuming a Firebird with 3x57 bulbs, first try removing the bulb and turning it 180 degrees before reinstalling.
Failing that, use a test light or multimeter to check for proper power and ground on the contacts inside the socket. The two contacts closest to the center of the socket slot are power and ground for the dim filament. The two contacts closest to the outboard edge of the slot are power and ground for the bright filament.
The problem is definitely not under the dash. The bulbs are not wired separately from the front of the car so if any bulb works there is nothing wrong with the wiring from the dash to the back of the car.
Again, assuming a Firebird with 3x57 bulbs, first try removing the bulb and turning it 180 degrees before reinstalling.
Failing that, use a test light or multimeter to check for proper power and ground on the contacts inside the socket. The two contacts closest to the center of the socket slot are power and ground for the dim filament. The two contacts closest to the outboard edge of the slot are power and ground for the bright filament.
Thread Starter
Teching In
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Sorry, yes it's a Firehawk (LT1) and I think it has a different socket type than the later F-body. The bulb inserts and then twists to lock instead of the flat tab that inserts straight into the socket.
Would putting a new socket/harness at that station help?
Would putting a new socket/harness at that station help?
Joined: Nov 2003
Posts: 11,330
Likes: 346
From: Jacksonville, FL (originally from Toronto Canada)
The 1157/2057 style sockets are actually easier to test. The outer metal casing that the bulb slides into is ground. There are two contacts on an insulator at the bottom of the socket - one is power for the dim filament and the other is power for the bright filament.
Use your test light or multimeter to test those contacts. Also, try swapping the bulbs between the socket that works and the one that doesn't. If the problem switches position with the bulb then the bulb is defective. If the problem stays in the same place then the socket or the wiring up to it are the problem.
Use your test light or multimeter to test those contacts. Also, try swapping the bulbs between the socket that works and the one that doesn't. If the problem switches position with the bulb then the bulb is defective. If the problem stays in the same place then the socket or the wiring up to it are the problem.
Thread Starter
Teching In
Joined: Jul 2007
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Well, I had already tried using one of the other turn signal bulbs in there and it did the same thing where the marker light clicked on instead of the turn signal... unless I had both bulbs installed wrong. 
Will have to try that test next.
Could be a bad socket though as the car had been in an accident with the left rear fender being replaced, but this socket is on the right side. I'm just wondering if the wiring got messed with somehow as one of my left sockets is not the original socket and does not fit into the tail-light housing very well. It's obvious that that socket is not correct as the wiring is non-standard.
The joys of used cars and not being the original first owner...
Will have to try that test next.Could be a bad socket though as the car had been in an accident with the left rear fender being replaced, but this socket is on the right side. I'm just wondering if the wiring got messed with somehow as one of my left sockets is not the original socket and does not fit into the tail-light housing very well. It's obvious that that socket is not correct as the wiring is non-standard.
The joys of used cars and not being the original first owner...
Joined: Nov 2003
Posts: 11,330
Likes: 346
From: Jacksonville, FL (originally from Toronto Canada)
Most aftermarket sockets use three wires colored white, brown, and black. The factory wiring for the left side has yellow (brake/turn signal), brown (tail/running lights), and black (ground). Check that the replacement socket wires have been connected to the correct factory wires... black to black, brown to brown, and white to yellow. If the white and brown are reversed you'll get the symptoms you describe.
