Side marker behavior

Gotta love that wiring . . .
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markintheair
Posts: 56
Joined: Fri Oct 12, 2012 7:44 am
Your car is a: Fiat 124 Spider 81 FI - Corsa Rosso
Location: The Netherlands

Side marker behavior

Post by markintheair »

Hi everyone,

What is the factory default behavior of the parking lights / side markers / indictors?
I have an '81 FI spider that I have restored and I have wired the front side markers, high beams, low beams & indicators in the front bumper according to Brad Artigue's schematics.

I have upgraded all side markers to LED lights.

When I turn the light on, all lights turn on, including the indicators (and side markers). When I turn on the indicator, nothing happens. All lights just stay on permanently.

When I disconnect the yellow wire between the connector & the light, the indicator works fine. See schematic below:

Image

Am I missing something?
Only the fool looks at a finger that points at the sky.
'81 FI Spider 2000
spider2081
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Your car is a: 1981 Spider 2000
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Re: Side marker behavior

Post by spider2081 »

When I turn on the indicator, nothing happens.
I'm not sure I understand this statement. What do you mean when you say "indicator"
markintheair
Posts: 56
Joined: Fri Oct 12, 2012 7:44 am
Your car is a: Fiat 124 Spider 81 FI - Corsa Rosso
Location: The Netherlands

Re: Side marker behavior

Post by markintheair »

Sorry, English is not my first language.

I mean when I pull the lever to indicate left or right, nothing happens. Another description would probably be "turn signal lever" I guess?
Only the fool looks at a finger that points at the sky.
'81 FI Spider 2000
spider2081
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Re: Side marker behavior

Post by spider2081 »

no problem my wife has been telling me for 60 years to learn English and I was raised with it.
The 4 lights on the side of the car are "running lights" or "Parking lights" only they were not wired to be turn signal lights.
markintheair
Posts: 56
Joined: Fri Oct 12, 2012 7:44 am
Your car is a: Fiat 124 Spider 81 FI - Corsa Rosso
Location: The Netherlands

Re: Side marker behavior

Post by markintheair »

spider2081 wrote:no problem my wife has been telling me for 60 years to learn English and I was raised with it.
The 4 lights on the side of the car are "running lights" or "Parking lights" only they were not wired to be turn signal lights.
Haha!

Thanks. And the front parking lights / turn signal?

Image

If I connect them exactly as in the picture, these lights are permanently turned ON. Turning on my turn signal lights via the lever on the steering column doesn't do anything. They just stay ON. When I disconnect the yellow wire between C1 & my front parking & turn signal, the light stays of until I turn the turn signal lights on. But then I'm left with an exposed wire...

Gotta love that wiring :P
Only the fool looks at a finger that points at the sky.
'81 FI Spider 2000
spider2081
Patron 2024
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Joined: Fri Jan 27, 2006 11:45 pm
Your car is a: 1981 Spider 2000
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Re: Side marker behavior

Post by spider2081 »

At the 2 pin bullet connector the yellow wire is the "parking light" wire and the Lt blue wire is the Turn signal wire. The front light bulbs have 2 filaments, One for parking lights and one for turn signal. (2 lights in one bulb). Is the correct bulb installed in the front bumper lights?
The headlight switch on the dash has 3 positions. Up is off, Center is parking lights powered from the "hot all the time" circuit, and down is headlight and parking lights powered by the "hot in start and run" positions of the ignition switch. The dash headlight switch has to be in the full up position for the parking lights not to be lit.
The mirafiori.com web site has a library for members. Membership is free. The library has a Fiat publication titled " Spider 2000 Electrical Diagnostic Manual 1980-1981" I think its a great booklet for understanding how the Spiders electrics should work.
I also have a 1981 Spider and am familiar with its electrical circuits. You can email me direct if you like: flyme194@gmail.com
JBeau
Posts: 22
Joined: Mon Apr 18, 2022 5:36 pm
Your car is a: 1978 Spider

Re: Side marker behavior

Post by JBeau »

There are potentially a couple of other things to check, especially since you've changed bulbs to LED:

1. Make sure you are using a flasher relay (under the driver's dash, not with the rest of the relays) that is rated for LED bulbs. As far as I understand, there is not enough draw from an LED to activate a standard flasher relay.

2. Check the polarity/orientation of the bulbs in the turn signals. Unlike incandescent bulbs, installation direction makes a difference, for reasons I cannot recall right now. I just know that I spent about a month of weekends diagnosing strange turn signal behavior (left indicator made all the lights in the car flash) that was remedied by removing and reversing the bulb in the front right turn signal. I felt like a fool, but learned loads about the wiring in my car.

Good luck!
18Fiatsandcounting
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Re: Side marker behavior

Post by 18Fiatsandcounting »

JBeau wrote:Unlike incandescent bulbs, installation direction makes a difference, for reasons I cannot recall right now.
Good point, and this may be part of the issue with the OP's lights. An LED is a Light Emitting Diode, and like most diodes, it does have a polarity. Negative to the cathode and positive to the anode, although that may be hard to tell by looking at the diode. There won't be any light when they are reversed biased, but you run the risk of destroying the LED due to what's called "avalanche breakdown". Some LEDs have an internal circuit to prevent damage when reverse biased, but I don't know if this is true for car LED lights. I believe it is true for house LED lights where it's common to get the socket wired incorrectly.

-Bryan
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