Left Turn Signal malfunctioning
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2nd Gear
Joined: Oct 2009
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Left Turn Signal malfunctioning
I need help diagnosing an semi-functioning Left turn signal on my 73 roadster. This car has been virtually frame-off restored and carefully put back together. I've replaced all the factory grounding straps.
The Left turn signal operates only occasionally, usually during the first 15 minutes of driving. When the Left signal quits working, both front and rear bulbs are lit. The Right side is perfect. All bulbs and sockets have been checked . All wiring has been visually checked for breaks, chafing,and/or pinched areas. All of this was cleaned and checked during re-assembly.
One odd thing happens: when the R signal is activated, (and the Left when it works), the Side Marker Lights blink alternately with the turn signals. No one can tell me if this is correct. I'm great at taking things apart and putting them back together, but my electrical diagnostic skills are weak.
Can someone point me in the right direction? This is driving me crazy.
Thanks.
Lew Filman
1973 L-82 Roadster
The Left turn signal operates only occasionally, usually during the first 15 minutes of driving. When the Left signal quits working, both front and rear bulbs are lit. The Right side is perfect. All bulbs and sockets have been checked . All wiring has been visually checked for breaks, chafing,and/or pinched areas. All of this was cleaned and checked during re-assembly.
One odd thing happens: when the R signal is activated, (and the Left when it works), the Side Marker Lights blink alternately with the turn signals. No one can tell me if this is correct. I'm great at taking things apart and putting them back together, but my electrical diagnostic skills are weak.
Can someone point me in the right direction? This is driving me crazy.
Thanks.
Lew Filman
1973 L-82 Roadster
Race Director
Joined: Mar 2003
Posts: 11,608
Likes: 780
From: Eustis ( Area 51 Bat Cave ) Fl
Not saying you didn't rebuild it perfect but being that it's been rebuilt puts a different slant on it,
I read your story about 3 times to be sure I get it, I like wiring and trouble shooting it,
Most times when I do a full build I toss out most if not all factory wiring,
The turn signal should not blink the side marker,
So from all the information you have given I am going to take a wild guess something is going on in the steering column/hazard wiring
Check hazard lamps, it's a whole different flasher unit,
Then be sure the column wiring is correct and no shorts or wrong contacts are being made in the turn signal switch itself.
I read your story about 3 times to be sure I get it, I like wiring and trouble shooting it,
Most times when I do a full build I toss out most if not all factory wiring,
The turn signal should not blink the side marker,
So from all the information you have given I am going to take a wild guess something is going on in the steering column/hazard wiring
Check hazard lamps, it's a whole different flasher unit,
Then be sure the column wiring is correct and no shorts or wrong contacts are being made in the turn signal switch itself.
Race Director
Joined: Mar 2003
Posts: 11,608
Likes: 780
From: Eustis ( Area 51 Bat Cave ) Fl
Could be...but if the hazard flasher work okay they use the same ground and that takes us another step in solving it,
I assumed since he mentioned the ground straps were installed that he connected the lamps grounds....hum.
I have seen on some cars where bubba got at the wiring have the flasher installed backwards ( normal wiring will not allow this ) cause issues,
I worked on a car once that only had signals if the column was in certain postions.
I assumed since he mentioned the ground straps were installed that he connected the lamps grounds....hum.
I have seen on some cars where bubba got at the wiring have the flasher installed backwards ( normal wiring will not allow this ) cause issues,
I worked on a car once that only had signals if the column was in certain postions.
Race Director
Joined: Mar 2006
Posts: 14,112
Likes: 28
From: Florida
Both the 77 I just sold and my 75 both alternate the side marker lamps when flashing. Not sure on your 73, but since it does it, probably correct.
If you didn't take apart the front signal and marker wiring, then it is factory, Has nothing to do with the flasher or signal switch.
For the 15 minute thing, old bulb sockets can test good and still fail intermittantly. The are only crimped inside and with age and oxidation can fail from just the heat of a bulb or movement.
Get an electromechanical flasher instead of a thermal, a lot easier to test and diagnose with, not dependant on bulbs working.
If you didn't take apart the front signal and marker wiring, then it is factory, Has nothing to do with the flasher or signal switch.
For the 15 minute thing, old bulb sockets can test good and still fail intermittantly. The are only crimped inside and with age and oxidation can fail from just the heat of a bulb or movement.
Get an electromechanical flasher instead of a thermal, a lot easier to test and diagnose with, not dependant on bulbs working.
Race Director
Joined: May 2006
Posts: 16,528
Likes: 53
From: Dayton, Ohio
Race Director
Joined: May 2006
Posts: 16,528
Likes: 53
From: Dayton, Ohio
Lew cut a long piece of wire and ground one end to the alternator case or the neg term of the battery and push the other end in the left turn signal socket like this picture. If your problem goes away then your problem is the grounding to the socket.
Race Director
Joined: May 2006
Posts: 16,528
Likes: 53
From: Dayton, Ohio
Could be...but if the hazard flasher work okay they use the same ground and that takes us another step in solving it,
I assumed since he mentioned the ground straps were installed that he connected the lamps grounds....hum.
I have seen on some cars where bubba got at the wiring have the flasher installed backwards ( normal wiring will not allow this ) cause issues,
I worked on a car once that only had signals if the column was in certain postions.
I assumed since he mentioned the ground straps were installed that he connected the lamps grounds....hum.
I have seen on some cars where bubba got at the wiring have the flasher installed backwards ( normal wiring will not allow this ) cause issues,
I worked on a car once that only had signals if the column was in certain postions.
Grounds at many different junctions can drive a man to drink.
He installed the ground straps but the ground for the signal socket must find its way back to the ground strap. Could be a bad socket or the 3 wire connector between the socket and the harness and that ground strap. My money will be on the black wire in the 3 wire connector.
Turn signal flasher installed backwards ? I can't imagine why reversing the 2 wires on the flasher would matter. Maybe I missed your meaning.
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Race Director
Joined: Mar 2003
Posts: 11,608
Likes: 780
From: Eustis ( Area 51 Bat Cave ) Fl
Assumed......careful with that word when it comes to grounds. Grounds at many different junctions can drive a man to drink.
He installed the ground straps but the ground for the signal socket must find its way back to the ground strap. Could be a bad socket or the 3 wire connector between the socket and the harness and that ground strap. My money will be on the black wire in the 3 wire connector.
Turn signal flasher installed backwards ? I can't imagine why reversing the 2 wires on the flasher would matter. Maybe I missed your meaning.
Grounds at many different junctions can drive a man to drink.He installed the ground straps but the ground for the signal socket must find its way back to the ground strap. Could be a bad socket or the 3 wire connector between the socket and the harness and that ground strap. My money will be on the black wire in the 3 wire connector.
Turn signal flasher installed backwards ? I can't imagine why reversing the 2 wires on the flasher would matter. Maybe I missed your meaning.
I have seen a perfect dual element bulb test fine and short and burn wires,
I did "assume" that any rebuild is like a 100% NCRS perfect type thing,
I assume everything is new or cleaned and rebuilt as I would do and I know that isn't always the case,
I assume the lamps grounds are carefully hooked up and the sockets are like new,
Yep, I do assume too much many times....
