Faulty turn signal bulb

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  #1  
Old 04-27-11, 08:19 AM
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Faulty turn signal bulb

The left front turn signal bulb doesn't light on my '97 Chevy Vinture van. I replaced the bulb and bulb socket.That didn't help. I went to my machanic. He checked for short. No short. He said it was a faulty "module" of some sort that controls the the left turn signal that has to be replaced.$360.00 plus labor.OUCH! I'd like a second opinion before I cough that much for a bulb that won't lit.
There are no other electrical problems with this vechicle.

Haywire
 
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  #2  
Old 04-27-11, 10:27 AM
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To light, the bulb needs 12V and ground. Check to see if the ground is good and if the 12V is there when called for.
 
  #3  
Old 04-27-11, 11:01 AM
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Thanks for the tip. The ground and 12v checkout ok.
 
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Old 04-27-11, 11:41 AM
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No offense...but that makes no sense. If the 12V and ground are ok...then the bulb would be lit. Could you explain what you mean by "ok"?

Also...if the left rear works..then odds are its a wiring problem.
 
  #5  
Old 04-27-11, 01:19 PM
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My mechanic said he check the wiring and found it ok. Based on that I assumed he also checked the voltage and the ground.
 
  #6  
Old 04-27-11, 01:25 PM
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Never assume anything with repairs....maybe he did..maybe he didn't. What about the left rear....? Emergency flashers?

I'll check the wiring diagrams later, if they are available online somewhere. Most times the sides are connected somewhere after the control module.
 
  #7  
Old 04-27-11, 01:55 PM
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On the turn signals on this car, the front left and right have 2 lights per signal, one facing the the front and one facing the side. The rear has just one on each side.When I put the flashers on, all work except the left light facing the front. This is the one that's out when put on the left turn signal.
 
  #8  
Old 04-27-11, 03:37 PM
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The left rear turn signal on my wife's 03 merc used to quit working on a regular basis. The bulb never blew and would work if it was reinserted although I did try changing the bulb and using that dialectic grease. Nothing seemed to help. Finally I ran a ground wire from the socket to the body - that was a yr or 2 ago and I haven't had to work on the light since

I don't know if that will fix your problem but it doesn't cost much to find out
 
  #9  
Old 04-27-11, 04:13 PM
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I don't think I can ground the socket. The socket is plastic and the housing it fits into is plastic. Nothing metal I can run a ground to. The only thing I can think of is if one of the 3 wires going to the socket is a ground. I could bare it and run a wire to the body. The 3 wires are blue,black and brown.
 
  #10  
Old 04-28-11, 06:02 AM
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I think that's what I did - ran a ground wire from the ground wire at the socket. The black wire is probably the ground but you should check it out first with a volt meter.
 
  #11  
Old 04-28-11, 06:17 AM
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Looking at the basic schematic available at Autozone...it has to be a ground if the socket has 12V. Its a pretty basic looking circuit... No electronic modules for those functions...just switches, wires, and the flasher. Again...that's based on Autozone info.

EDIT

Hmmm....reading your post on wire colors leads me to believe you may have wiring for a '96. It lists brown, light blue, and black wires. A '97 is listed as having yellow, brown, and black. AND..on a '96 the left front turn signal DOES connect to the headlight switch but thats only for the running lights i believe...which appears to be the brown wire. The turn signal sure looks like it should be the blue.

They share a ground either way...so if the running light works at normal brightness, your ground should be ok.

Still don't see any control modules like you see on newer vehicles...basic switches and wires only.
 
  #12  
Old 04-28-11, 07:05 AM
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The socket I replaced has black, brown, and pale blue wires. The one I replaced it with has, black, brown and a brighter blue wire.

Regarding the running lights; the left turn signal light, that doesn't work, is also the running light. In the daytime this light is not on but at night time, with the head lights on, that running light is on.
 
  #13  
Old 04-28-11, 07:28 AM
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Right...that agrees with the wiring diagram I found for a '96. Aftermarket replacement parts might be slightly different in color coding...but blue is still blue.

I'd ask the guy exactly what part he wants to replace. I don't see any electronic modules here at all. He may want to replace the turn signal switch, which I think would be a waste of money.

A simple test probe from the parts store will tell you if you are getting voltage. Did the new socket have a pigtail with a connector that plugged into the wiring harness? I'd start checking back from that point. It could just be a loose or corroded connection.

If you can read schematics...you can look it up at Autozone.
 
  #14  
Old 04-28-11, 08:38 AM
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I can tell by the threads that there is a question of wheather I should replace an expensive module.

My plan now is to find an auto elecrtic mechanic with the hope that he will find the problem closer to what your opinions are.

Everybody, thank you for the help you've provided me.

haywire09
 
  #15  
Old 04-29-11, 06:07 AM
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I'm with the turn signal module

My son's 97 Lumina (sedan) had a no brake lights problem. Module at the steering wheel resolved that to the tune of $360.

His next car (97 blew head gasket), 98 Lumina (sedan) had a brakes lights work so as long as you're not braking with the turn signal on - if so, no brake light on the light opposite the turn signal - turn signal light would still blink.

Solution? You guessed it, same module at the steering wheel just like his 97. This one at $366.

Power locks not working on either of his Luminas - Module in back dash culprit. He can use the key just like I did with my car when I was in high school. On his 98, that one too blew the head gasket but I had it fixed to the tune of $500. No more Luminas for the kid.

Hope that helped.
 
  #16  
Old 04-29-11, 01:39 PM
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I'm still hanging tough about spending $360.00 for a module, not including labor, for a left front turn signal bulb that doesn't work when all the other electrical componants on the car do work.

And still pursuing the possibility that it's a voltage or a ground problem.

haywire09
 
  #17  
Old 04-30-11, 01:16 PM
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If the front does not work and the rear does its not the module. It either in the socket or the wiring harness
 
  #18  
Old 04-30-11, 01:37 PM
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That was my thinking. When I turn on the left turn signal, 3 lights are suppose to flash. One in the back and two in the front. The front has one facing to the side and the other facing to the front. Back and side lights flash. the one facing front does not.

haywire09
 
  #19  
Old 04-30-11, 01:48 PM
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That's what I've been saying...it's a wiring or connector problem...possibly a switch, but I'm not going back to Autozone to look at the schematics again..lol.
 
  #20  
Old 05-08-11, 10:11 AM
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The left turn signal now works. As memtioned in my other treads, I have 2 front left turn signal/running lights, one facing the side and the other facing front. The front didn't work. The front light socket has 3 wires: black, brown and blue. The side has just 2: brown and yellow.

I checked the front socket with a test light.The socket has 3 contact inside it.The ground contact checked ok and the other 2 had vlotage to them. I guesed the yellow and the blue were for the turn signal and spliced them together. The turn signal now works.

Not knowing much about auto electric, I still don't understand, if I'm getting voltage to the socket and the ground is good, why didn't the turn signal work? Also as before: the front left running light only comes on at night when the head lights are on?

Thanks everyone for your comments.
 
  #21  
Old 05-08-11, 10:38 AM
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Did you look even at the schematic at Autozone? I'm not going back....but I'm sure what you did was splice the side supply to the front supply. Eliminating the BAD wire or connection that prevented it from working.

Hey...it's 14 years old...if it works it works....
 
  #22  
Old 05-08-11, 01:18 PM
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I did not look at the schematic. If I did I probably would not understand it. My thinking was I'd try this and if it didn't work I'd take it to an auto electric shop.
 
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