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turn signal light stays on when headlights on

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Old 12-27-2015, 01:35 PM
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Default turn signal light stays on when headlights on

My sister bought a 2002 Trans Am a few months ago and the front DRL/turn signal housings were bad. I ordered two new ones and also got two new sockets to rebuild. I put the housings in and did the passenger side socket no problem. The drivers side socket had already been replaced with some other type of socket, so I have to splice the wiring together instead of being able to rebuild the socket. After putting everything back together when the headlights are on, the drivers side turn signal indicator on the gauge panel stays lit up. If you manually move the drivers signal up and down the back signal lights up, but the front does nothing.

When turning on the hazards the light will blink as it should. I tried replacing the flasher relay thinking that is what caused it, since the hazard lights work, but that still did not fix it. Does anyone have any idea what the problem could be or what wire out of the 3 I need to look it. Its just odd it works fine without the headlights on, and that even with the headlights on the hazards still work.

Also not sure if this helps for troubleshooting, but when I had the flasher out the turn signals obviously did not work, however when I turned the headlights on the left turn signal indicator still lit up on the dash.

Thanks for any help,
Brandon

Last edited by brandon1221; 12-27-2015 at 09:31 PM.
Old 12-27-2015, 03:06 PM
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This is normal. The bulbs have two filaments. One for the Parking Lights (illuminated when the parking lights or headlights are selected) and a second filament for the turn signals and DRL's.

It sounds like what you have is a burned out parking light filament on your passenger side.

In short, the lights should be "on" 100% of the time and should only go "off" when they are flashing during the daytime or when the car is turned off. (When they flash at night, they should become double-bright.)
Old 12-27-2015, 05:11 PM
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Originally Posted by wssix99
This is normal. The bulbs have two filaments. One for the Parking Lights (illuminated when the parking lights or headlights are selected) and a second filament for the turn signals and DRL's.

It sounds like what you have is a burned out parking light filament on your passenger side.

In short, the lights should be "on" 100% of the time and should only go "off" when they are flashing during the daytime or when the car is turned off. (When they flash at night, they should become double-bright.)
I put brand new bulbs in when re-doing everything, although I guess it is possible I got a bad bulb. However if it was the filament in a bulb, wouldn't the hazards also not work with headlights on? I figured since the hazards work when the headlights are on or off and the turn signal only does not work when the headlights are on (which is also when the indicator light turns on), it would not be a bulb problem.

I will try switching the bulbs from one side to another and see if it follows and is in fact the bulb.
Old 12-27-2015, 08:21 PM
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OK. I was making some assumptions about what you meant by "turn signal" and if it was a term for the parking light and turn signal/DRL or just the turn signal.

If:
- Your lights are solid amber when the headlights are on and your turn signals are "off" AND
- Your hazards work normally

then it could be the flasher.

Your OEM flasher is a thermal-type and relies on the current flowing through it to "flash." Your headlights being on will cause a certain amount of voltage drop in the car's electrical system and each side of the car has a different resistance, (your splices can also contribute to this) so it's possible that your flasher is borderline and just one side is in a condition where there isn't enough current flowing to make the flasher flash.

The hazards and turn signals use the same wiring past the turn signal assembly. If everything works with the ligths off, that proves the turn signal assembly works fine. There is also a chance your DRL module could have a problem. It takes the headlights in as an input. (During the day, it flashes your DRL's "off" when you turn the signals on and at night, if flashes them "on" to make the bulbs double bright.) The DRL module is expensive and I'd do some extensive electrical tracing before replacing it. So, I'd replace the $5-$10 flasher as a first step if you meet the conditions above.
Old 12-27-2015, 09:29 PM
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Originally Posted by wssix99
OK. I was making some assumptions about what you meant by "turn signal" and if it was a term for the parking light and turn signal/DRL or just the turn signal.

If:
- Your lights are solid amber when the headlights are on and your turn signals are "off" AND
- Your hazards work normally

then it could be the flasher.

Your OEM flasher is a thermal-type and relies on the current flowing through it to "flash." Your headlights being on will cause a certain amount of voltage drop in the car's electrical system and each side of the car has a different resistance, (your splices can also contribute to this) so it's possible that your flasher is borderline and just one side is in a condition where there isn't enough current flowing to make the flasher flash.

The hazards and turn signals use the same wiring past the turn signal assembly. If everything works with the ligths off, that proves the turn signal assembly works fine. There is also a chance your DRL module could have a problem. It takes the headlights in as an input. (During the day, it flashes your DRL's "off" when you turn the signals on and at night, if flashes them "on" to make the bulbs double bright.) The DRL module is expensive and I'd do some extensive electrical tracing before replacing it. So, I'd replace the $5-$10 flasher as a first step if you meet the conditions above.
Flasher has already been replaced and did not fix it. Also I found it odd when the flasher was removed and I turned the headlights on the left turn signal indicator still came on in the dash. Although if I turned on my right turn signal nothing would come on, or if the headlights were off and I turned any signal on nothing happened since there was no flasher

I guess I might try replacing the socket, maybe I just got a bad socket....But would anything wrong with the socket cause the left turn signal indicator on the dash to light when the headlights are on, even with the flasher relay removed?

Last edited by brandon1221; 12-27-2015 at 09:37 PM.
Old 12-28-2015, 06:35 AM
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Make sure your headlight is grounded. sounds like it's back feeding power
using the turn signal as the ground. Pull the turn signal bulb and see if the
headlight comes on.
Old 12-29-2015, 11:10 AM
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Originally Posted by brandon1221
I guess I might try replacing the socket, maybe I just got a bad socket....But would anything wrong with the socket cause the left turn signal indicator on the dash to light when the headlights are on, even with the flasher relay removed?
No, the socket would be fine. As you saw, they aren't complicated and there's now where for a short to occur. It's gotta be a wiring issue.

Probably something related to the ground, or a bizarre back-feed as nofun points out. ^ It's time to either double check all the wiring and grounds or get out the electrical tester and schematic. Circuits are getting crossed when that second parking light filament is getting energized by your headlight switch...
Old 12-30-2015, 10:53 PM
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I have also seen this caused by bulbs before. If a two filament bulb shorts across internally, it can send voltage down the other circuit. I would pull every bulb that is used in turn signal, as well as parking light.

That would be your amber fronts, and your rear dual filament bulbs. Can't remember, but if the marker lights on the sides of the vehicle flash as well, you will want to pull them too.

Pop all of those bulbs out, and then post back if your turn indicator lights up again. If not, start plugging bulbs back in until you find the culprit!
Old 01-04-2016, 09:07 PM
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Originally Posted by brandon1221
the drivers side turn signal indicator on the gauge panel stays lit up.

Brandon
Originally Posted by wssix99
This is normal. The bulbs have two filaments. One for the Parking Lights (illuminated when the parking lights or headlights are selected) and a second filament for the turn signals and DRL's.
This isn't normal, basically his left turn signal is ALWAYS on, because the green left turn arrow on his gauge cluster is always illuminated. The DRL's on the Firebirds always remain on when the car is on but the gauge cluster turn signals do not illuminate.

Honestly it sounds like to me that the wire for your DRL is crossed with your turn signal wire at the socket when the new (and incorrect) socket was installed and you need to rearrange it. DRL receives constant power when the car is on, and now its giving constant power to your turn signal instead because the wire is crossed to the wrong circuit.
Old 01-04-2016, 10:40 PM
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Originally Posted by Need4Camaro
This isn't normal, basically his left turn signal is ALWAYS on, because the green left turn arrow on his gauge cluster is always illuminated. The DRL's on the Firebirds always remain on when the car is on but the gauge cluster turn signals do not illuminate.
It's hard to tell. I think we are still missing some nouns and verbs.
Old 01-06-2016, 02:47 AM
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I havent had a chance to look at the car and try anything because I have been busy with work. If it is something with the wiring, does anyone have a wiring diagram for the DRL/turn signal?
Old 01-06-2016, 08:47 AM
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You can now get them off of AutoZone's website.



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