1979 troubleshooting flashers
Thread Starter
7th Gear
Joined: Aug 2009
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From: Birmingham Michigan
1979 troubleshooting flashers
Simple question from new member:
all left side lamps light and flash, indicator flashes
all right side lamps light and don't flash, indicator solid on
Checked front and rear bulb for continuity (haven't checked side marker)
What next??? Thanks!
all left side lamps light and flash, indicator flashes
all right side lamps light and don't flash, indicator solid on
Checked front and rear bulb for continuity (haven't checked side marker)
What next??? Thanks!
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From: Eustis ( Area 51 Bat Cave ) Fl
The old mech flasher works by being a clicks off switch so to speak, when the load gets the metal in it hot it Clicks off for a second to cool off then back on, repeats to flash,
Not enough load on flasher, IE bad bulb will do what you have going on,
Bulbs and flashers are cheap to swap out for testing,
If I recall the warning lamps have their own flaser, try them.
Not enough load on flasher, IE bad bulb will do what you have going on,
Bulbs and flashers are cheap to swap out for testing,
If I recall the warning lamps have their own flaser, try them.
Thread Starter
7th Gear
Joined: Aug 2009
Posts: 7
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From: Birmingham Michigan
This is why I posted the question. All of the bulbs are fine (although I did replace them for kicks). Everything flashes properly with the emergency flash switch. It's just when I ask for a right turn: all of the right side bulbs (and the interior turn signal indicator) light but they don't flash. Of course, the rear side markers aren't in this circuit, but that's a given.
Is this a symptom of a defective flasher? I would have thought that the flasher is not sided, but I'm more of a body, paint, and trim guy. This stupid little thing is driving me nuts.
ps. If it's not raining in Michigan tomorrow, I'll add a picture of the car. My father was a GM plant manager in St. Louis, and this 79 was a bit of a one-off in the factory. It was slightly modified in Final Assembly.
Is this a symptom of a defective flasher? I would have thought that the flasher is not sided, but I'm more of a body, paint, and trim guy. This stupid little thing is driving me nuts.
ps. If it's not raining in Michigan tomorrow, I'll add a picture of the car. My father was a GM plant manager in St. Louis, and this 79 was a bit of a one-off in the factory. It was slightly modified in Final Assembly.
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From: Eustis ( Area 51 Bat Cave ) Fl
No, a flasher isnt left and right the turn signal switch decides which side it is going to flash, so the flasher is good, the bulbs are good and emergency flasher flashes both sides, the emergency flasher is a second flasher unit and all work because it's a larger load on it,
For turn signals,
The juice comes into the flasher unit then to the turn signal switch then to which ever side the switch is turned to,
try swapping lamps from left side to right side....
I have seen new bulbs not work right or odd things within a bulb happen,
If that doesnt work,
seems a look at the turn signal switch is next,
I took a quick look at the wiring diagram and there is no way I see for it to bypass the flasher unit,
What was modded on your car?
For turn signals,
The juice comes into the flasher unit then to the turn signal switch then to which ever side the switch is turned to,
try swapping lamps from left side to right side....
I have seen new bulbs not work right or odd things within a bulb happen,
If that doesnt work,
seems a look at the turn signal switch is next,
I took a quick look at the wiring diagram and there is no way I see for it to bypass the flasher unit,
What was modded on your car?
Last edited by The13Bats; Aug 23, 2009 at 06:30 PM.
Thread Starter
7th Gear
Joined: Aug 2009
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From: Birmingham Michigan
I'll try swapping the bulbs right/left. Can the turn signal switch cause the problem, if it is activating the right side lights, as intended? I thought the lights turn on, create the load on the flasher, and then they flash. I'll swap the lamps first.
The car was modified in the Final Finish area before it shipped. Exterior paint and stripe detail, and interior trim are atypical for the model year. And one-off pinstriping combines with the ground-effects to make the car look chunkier, rather than the norm. It's subtle, though. Most people just say that they really like the car, and don't pick up that it's a strange '79. My father decided to hold onto the car, once I bought a small-block '66 coupe with pipes and AC. He sent it up to me in 1997, and I've been keeping it relatively functional ever since.
The car was modified in the Final Finish area before it shipped. Exterior paint and stripe detail, and interior trim are atypical for the model year. And one-off pinstriping combines with the ground-effects to make the car look chunkier, rather than the norm. It's subtle, though. Most people just say that they really like the car, and don't pick up that it's a strange '79. My father decided to hold onto the car, once I bought a small-block '66 coupe with pipes and AC. He sent it up to me in 1997, and I've been keeping it relatively functional ever since.
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From: Eustis ( Area 51 Bat Cave ) Fl
Do I "believe" the switch is bad...no, I believe it's a lamp issue, but we will see.
Last edited by The13Bats; Aug 23, 2009 at 07:02 PM.
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From: Eustis ( Area 51 Bat Cave ) Fl
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From: Dayton, Ohio
fvetteandcbird look close at the right front signal and side marker with the emergency flashers on and see if only the side marker is flashing and not the turn bulb. If thats the case repair the ground for the R signal.
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From: Dayton, Ohio
Thats why I ask him that question.
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From: Eustis ( Area 51 Bat Cave ) Fl
He said above " Everything flashes properly with the emergency flash switch."
So that is why I asked how could a groud cause the problem only in turn mode....the grounds are the same be it hazzard or turn....different flasher units but same grounds.
So that is why I asked how could a groud cause the problem only in turn mode....the grounds are the same be it hazzard or turn....different flasher units but same grounds.
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From: Dayton, Ohio
As I said before there are other possibility's for ground. If it wasn't for the two side markers tying the right and left circuits together I would say it would not be possible. Do you have a GM troubleshooting wiring manual ? If so check it out and I think you can see what I mean.
One other thought. You talked about the flasher operation and its need for load to flash,what if this particular "emergency" flasher requires less load to flash ?
I think we need more info from the OP.
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From: Eustis ( Area 51 Bat Cave ) Fl
We both know that if the ground is working when the juice is coming from the Hazard flasher the ground should work when the juice is coming from the turn flasher if you take a peek at the wiring diagram you will see that nothing changes as far as grounds go,
Things do take different routes in the turn signal switch be it in hazard mode or turn mode,
The turn signal switch is dealing with the positive side and doesn't add a ground when in hazard mode.
Flasher units at least old mechanical ones are not really built to any specs,
Some do flash faster than others, some truck ones will handle more lamps,
I always stock up when I am at a u pull it junk yard,
And I have even adjusted the speed of a flasher but don't recommend it to the novice,
So you ask what if the flasher unit in the hazard circuit needed less load to flash?
Compared to what, the flasher unit in the turn system?
The hazard lights would just flash at a faster or slower rate, normally a burnt flasher unit will not do anything,
Most flashers will flash even one bulb just not very fast.
So when the turn is on for the right side the lamps just stay lit, so one wonders why isn't the flasher getting hot enough to click off...not enough load.
Yes, lets see what more the OP can tell us,
Things do take different routes in the turn signal switch be it in hazard mode or turn mode,
The turn signal switch is dealing with the positive side and doesn't add a ground when in hazard mode.
Flasher units at least old mechanical ones are not really built to any specs,
Some do flash faster than others, some truck ones will handle more lamps,
I always stock up when I am at a u pull it junk yard,
And I have even adjusted the speed of a flasher but don't recommend it to the novice,
So you ask what if the flasher unit in the hazard circuit needed less load to flash?
Compared to what, the flasher unit in the turn system?
The hazard lights would just flash at a faster or slower rate, normally a burnt flasher unit will not do anything,
Most flashers will flash even one bulb just not very fast.
So when the turn is on for the right side the lamps just stay lit, so one wonders why isn't the flasher getting hot enough to click off...not enough load.
Yes, lets see what more the OP can tell us,
Thread Starter
7th Gear
Joined: Aug 2009
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From: Birmingham Michigan
Resolution, thank to everyone's help. You were all sort of right. Everything I said was right, except for one thing difficult to see.
Root Cause: I originally must have had a defective (but not blown) bulb.
Secondary root cause: In the dim light and with my aging eyeballs, I had incorrectly installed one of the ten bulbs (as you all know the 1157 clears and ambers are sided).
Both of these conditions must have resulted in insufficient load for the flasher to function.
Argh. And thanks for the discussion.
Root Cause: I originally must have had a defective (but not blown) bulb.
Secondary root cause: In the dim light and with my aging eyeballs, I had incorrectly installed one of the ten bulbs (as you all know the 1157 clears and ambers are sided).
Both of these conditions must have resulted in insufficient load for the flasher to function.
Argh. And thanks for the discussion.
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Joined: Mar 2003
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From: Eustis ( Area 51 Bat Cave ) Fl
Very cool it worked out, I was sure in my mind it wasn't a ground problem in your case,
I thought about mentioning that dual element lamps only will fit the socket one way correctly,
But over time and different owners sometimes the socket gets "worn" a bulb can be installed backwards then the dim side would be on flash...equals low load and can short in the socket,
I have seen in one case a dual element bulb short out inside it, it burned up the rear wiring in a "velle,
Main thing is now things are working as they should,
Cheers,
P.
I thought about mentioning that dual element lamps only will fit the socket one way correctly,
But over time and different owners sometimes the socket gets "worn" a bulb can be installed backwards then the dim side would be on flash...equals low load and can short in the socket,
I have seen in one case a dual element bulb short out inside it, it burned up the rear wiring in a "velle,
Main thing is now things are working as they should,
Cheers,
P.
Thread Starter
7th Gear
Joined: Aug 2009
Posts: 7
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From: Birmingham Michigan
Yes. Thanks. Now that the flashers are working, the car suddenly wants to stall out while it's motoring down the road! Tank, fuel lines, fuel pump, and fuel filter have already been checked. Now on to the timing. This era had timing gears with plastic bits, and these deteriorate? Found that it will stall in the garage when I disengage the vacuum advance. But the flashers are beauty!
