'77 Spider, one side hazard blinks instead of turn signal - Alfa Romeo Bulletin Board & Forums
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post #1 of 9 (permalink) Old 06-13-2019, 07:27 PM Thread Starter
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'77 Spider, one side hazard blinks instead of turn signal

Hi All,

On my '77 Spider, when signaling a right turn, the hazard blinks instead of the turn signal. I suspect it's just wired up wrong. This also causes the blinker to flash slower because (I believe) the current draw of the hazard bulb is different than that of the turn signal changing the time constant, and also the over-steering wheel indicator doesn't flash (though I do hear the relay clicking). A left turn signal works correctly in all respects. I only have the black and white wiring diagrams from the Cardisc, does anyone have an easier to follow diagram diagram, and any idea of what color the relevant wires might be on the harness?

Thanks,
Zuofu

Last edited by Zuofu; 06-13-2019 at 07:39 PM.
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post #2 of 9 (permalink) Old 06-13-2019, 08:29 PM
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Quote:
Originally Posted by Zuofu View Post
On my '77 Spider, when signaling a right turn, the hazard blinks instead of the turn signal.
By "the hazard" do you mean the red button that you push to enable the hazard lights?

And what happens when you engage the hazard flashers?

Quote:
I suspect it's just wired up wrong.
Yea, probably. Sounds like something more serious than a poor ground.

Quote:
This also causes the blinker to flash slower because (I believe) the current draw of the hazard bulb is different than that of the turn signal changing the time constant
Yup.

Jay Mackro
San Juan Capistrano, CA

'63 Guilia spider
'65 Guilia Sprint GT
'67 Duetto
'91 164L
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post #3 of 9 (permalink) Old 06-13-2019, 08:41 PM Thread Starter
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Actually, I think hazard light is the wrong word, it's the parking light blinks instead of the turn signal (white lens flashes instead of yellow lens). My car has actually been upgraded to the euro-spec bumpers, *but* even with the old bumpers it would clearly flash a different bulb inside the yellow light housing (I believe there are two separate bulbs even though there's just one yellow lens), since the connector for the bumper lights was the same.

So doing a test of the behavior, it's actually quite weird:

If the headlights are off, the signaling a left turn causes the left turn signal to flash. Signaling a right turn causes the right parking light to flash.

If the headlights are on, both parking lights are on. Then signaling a left turn causes the left turn signal to additionally flash, signaling a right turn causes the right parking light to flash between bright and dim (dimming it off for part of the time, when the rear turn signal is on).

Pressing the hazard button causes the same behavior depending on whether the headlights are on or off. All the rear turn signals work correctly (except that the right turn flashing is slower due to the different time constant).

My guess is somehow the right turn got shorted to the right parking light, but the resistance of the parking light is lower (forming some sort of bootleg logical OR gate), but where to start looking for the short?

Last edited by Zuofu; 06-13-2019 at 08:54 PM.
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post #4 of 9 (permalink) Old 06-13-2019, 09:14 PM
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Sounds like a bad ground. Try running a jumper from the neg battery cable directly to the ground wire on the housing that is malfunctioning.
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post #5 of 9 (permalink) Old 06-13-2019, 09:53 PM
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Quote:
Originally Posted by Zuofu View Post
Actually, I think hazard light is the wrong word, it's the parking light blinks instead of the turn signal
Oh. In that case, 6alfas is right - it's simply a bad ground.

Jay Mackro
San Juan Capistrano, CA

'63 Guilia spider
'65 Guilia Sprint GT
'67 Duetto
'91 164L
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post #6 of 9 (permalink) Old 06-13-2019, 10:03 PM
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I had that happen on my '71. In my case, it was dirty sockets. All you need is for another path for the electrons to be easier to achieve an interesting result.

[FONT="Century Gothic"][B]Bob Farace[/B]
[COLOR="DarkGreen"]1971 Alfa Romeo 1750 Spider Veloce[/COLOR]
[I]Director, Connecticut branch, Scuderia Non Originale[/I][/FONT]
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post #7 of 9 (permalink) Old 06-14-2019, 03:18 AM
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Quote:
Originally Posted by Zuofu View Post
...On my '77 Spider.....any idea of what color the relevant wires might be on the harness?...
according to Jim's great colored diagram it is blue for the blinker and yellow for the park light.
here is a snippet

though what you have certainly sounds like a typical ground problem.
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Dom - Alfa Spider 1990 S4 - formerly: Alfa 101 Sprint, 2600 Sprint, Montreal - family classics: Jensen Interceptor II, '58 Hooper RR Silver Cloud I, Shadow II, '60 Corvette.
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post #8 of 9 (permalink) Old 06-14-2019, 06:52 AM
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Great suggestions^^.

Why not just refresh all the grounds on the car and clean/inspect all the bulb sockets and bulbs? One bulb could be in backwards.

This is considered maintenance on a 42 year old car......

It's Giuseppe's giubos, not Guido's guibos, on my 78 Alfas
REFRESH CONNECTIONS BEFORE REPLACING COMPONENTS
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post #9 of 9 (permalink) Old 06-14-2019, 10:39 AM Thread Starter
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Confirmed, totally a bad ground - in fact a disconnected ground.

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