Hazard switch not working in "on" position

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mrspeed
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Your car is a: 1975 Fiat 124 Spider

Hazard switch not working in "on" position

Post by mrspeed »

I've now spent two nights trying to figure out why my blinkers weren't working. The good news is after studying the following wiring diagrams, and spending a bit of time poking and prodding with the multimeter and jumper wires, I was able to trace the issue to the fact that the hazard switch was in the "on" position instead of the "off" position, and so power wasn't being sent from the hazard switch to the turn signal switch.

However, this meant I had a new problem, which is that it wasn't my turn signals that weren't working after all, it was my hazard lights that weren't working (hence why I didn't realize the switch was in the "on" position instead of the "off" position).

I've completely disassembled the hazard switch and cleaned the contacts, and I can tell with the multimeter that when the switch is off, power is going from the light blue wire terminal to the gray wire terminal. However, when it's "on", no power is going from light blue wire terminal to the purple and red wire terminals.

I know it's not a grounding issue, because I can connect the purple and red wire terminals directly to ground through the multimeter and still get zero voltage. Furthermore, I can jumper the light blue wire terminal to the purple wire terminal, and my hazards come on.

Upon closer examination of the inside of my hazard switch, I honestly can't even see how the light blue wire terminals could ever be connected to the purple and red wire terminals with the rocker switch in either position. In the "off" position, I can see how the bottom brass piece connects the two bottom terminals, but in the "on" position, there is nothing physically connecting the bottom terminal to the top terminal.

The only pieces inside my switch are the terminal contacts, and the two bent brass tabs, along with the spring-loaded arms on the rocker switch. Is there supposed to be a third tab or something that connects the bottom terminals to the top terminals when the tabs are pushed the other way?

To summarize, I guess my question is, am I missing something, or is my switch missing something?

https://www.mirafiori.com/faq/content/F ... iagram.htm

https://www.mirafiori.com/forum/viewtop ... 8c68980282
1975 Fiat Spider
spider2081
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Re: Hazard switch not working in "on" position

Post by spider2081 »

I believe the 76 Spider uses 2 flashers one for signal lights and one for hazards. Also the signal lights are powered from the "hot in start and run" circuit in the car and the Hazards are powered from an inline 16 amp "hot all the time" fuse. The rectangle shaped switch directs the proper power to the correct flasher. The inline fuse is usually located behind t he dash in the area of the fuse panel. The hazard flasher is mounted to the fire wall behind the instrument cluster.
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Re: Hazard switch not working in "on" position

Post by mrspeed »

Thanks for the input. The flasher units all work, since when I jumper the input to the output of the hazard switch, the hazards do come on.

Yes, the hazard flasher is a separate unit on the left side of the steering column than the turn signal flasher unit on the right side of the column, as shown in the diagrams I posted above. However, if you look at the wiring diagram, the power that goes to the turn signal switch on the steering column actually does come from the hazard switch (unless I'm misreading it, but my car seems to match my understanding of what the wiring diagram says). I believe this is so that when your hazards are on, the circuit doesn't compete with the turn signals and have two flasher units sending power to the lights. I.e. the hazard switch either sends power to the flash unit or to the turn signal switch, but not both.

The problem I'm having is that the switch works in the "off" position in that it sends power to the turn signal switch, but it doesn't work in the "on" position in that it's not sending power to the hazard flasher unit. If I put it in the "on" position but jumper the power input to the hazard flasher output, the hazard lights start flashing.
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Re: Hazard switch not working in "on" position

Post by spider2081 »

Got it. I missed understood what you were saying.
Sounds like a defective hazard switch. They can often be opened and the contacts cleaned. Some time the innards fly but but with a little thought it can be reassembled.
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Re: Hazard switch not working in "on" position

Post by mrspeed »

No problem. You've actually hit on the main question I was asking. I did take apart the switch and clean the terminals.

The main thing I'm wondering is if anyone has experience taking these apart, because I'm looking at the internals, and there is no part internally that would ever connect the input power to the hazard flasher output terminal in either position. I'm wondering if my switch is missing a piece inside.
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Re: Hazard switch not working in "on" position

Post by mrspeed »

Ok, finally able to upload some pictures. Notice in the second picture that when the contacts are rocked to the right, the bottom middle terminal connects to the bottom right terminal. This is the flasher circuit.

When the contacts rock to the left, the top middle two contacts connect to each other, which is consistent with the wiring diagram. But the bottom middle terminal does not connect to the top middle terminals as the wiring diagram indicates that it does.

Image

Image
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Re: Hazard switch not working in "on" position

Post by spider2081 »

Its been too long since I have had one apart to be sure. I am thinking the wrong hazard switch is in your car.
I believe the light is connected to the dash dimmer and is for switch illumination. There is another light on the dash that lights from the hazard flashers when they are working.
The light connections use 2 of the connections on the back of the switch. The other connections switch the correct power to the correct flasher. Quickly looking at your photos I agree it can't happen.
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Re: Hazard switch not working in "on" position

Post by mrspeed »

Thank you, I appreciate the confirmation. I have no problem buying a new Switch, honestly it was just driving me nuts not being able to figure it out. In fact, when I do order the new one I'll probably end up disassembling it for comparison before I install it just out of sheer curiosity. I'll update this thread when I do.
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Re: Hazard switch not working in "on" position

Post by spider2081 »

I was on my way out the door when I made the last reply. Looking at your photos I was thinking the switch base contacts on the left are for the internal light. one side connects to ground and the other is power from the instrument dimmer.
I thought the original switch had the movable contacts facing opposite directions. Your photo has both facing in the same direction. This makes both on or off at the same time. I don't see how this can work per the wire diagram.
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Re: Hazard switch not working in "on" position

Post by mrspeed »

Hmm, I did have the thought of flipping the top tab 180 degrees, where switching it one way could make it contact the power lead from the little light bulb, but I didn't do that because a) I have no idea how that'd actually work with the light bulb copper tab that comes down to rest on that lead to power the lightbulb in the switch, and b) the top tab has a little foot and not actual contact on the end of it, which indicated to me that the end of that tab isn't supposed to contact anything electrical and instead only rest on the plastic housing.
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Re: Hazard switch not working in "on" position

Post by spider2081 »

I have a number of t he round Hazard switches but none of the rectangular so I cant check it one to see how it operates. It just seems to me that one set of contacts has to be "on" in one position and the other set "on" in the other position.
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Re: Hazard switch not working in "on" position

Post by mrspeed »

spider2081 wrote:I have a number of t he round Hazard switches but none of the rectangular so I cant check it one to see how it operates. It just seems to me that one set of contacts has to be "on" in one position and the other set "on" in the other position.
That's the idea. Here's a marked up picture. According to the wiring diagram, when the hazards are off, the bottom middle terminals are supposed to be connected to the bottom right terminal (pink line). This sends power to the turn signal switch on the steering column.

When the hazard switch is on, it's supposed to connect the top two middle terminals to each other, as well as connect the bottom middle terminals to the top middle terminals (blue lines). The latter connection (vertical blue line) is what sends power to the hazards, but as far as I can tell, that vertical connection can't happen in my switch.

The left two terminals just connect to the bulb inside the switch.

Image
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Re: Hazard switch not working in "on" position

Post by mrspeed »

As an update, I finally ordered a new hazard switch, but it does the exact same thing as the old hazard switch. My hazards continue not to work in the on-position, unless I manually jumper the power terminal to the hazard terminal.

Does anyone have working hazards with my style of switch that'd be willing to verify that their switch does in fact send power to the hazard terminals while on? For bonus points, would anyone with this style of hazard switch that works be willing to open it up and see how the two terminals are connected inside the switch? It takes about 2-5 minutes to disconnect the switch from the car and open it up. Recommended to have small electronics pliers to help reposition the internal contacts when you close the switch back up.
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Re: Hazard switch not working in "on" position

Post by spider2081 »

A friend of mine had a spare switch so I checked it out with an ohm meter.

The light contacts are simply a light to illuminate the switch in the dash. I believe the light should be lit whenever the lights on indicator is lit.
The light wires for this switch are white/black (ground) and gray/red (power)
The hazard flasher contacts are the top center contacts The center contact has 2 wires in it. a dark blue/white and a violet wire. I think this is power to the switch. The red wire is switched power to the hazard flasher. Are these the wires you jump to make your hazards work?
The hazard switch contacts connect these wires when t he hazard symbol ( triangle) is pushed down.
When the word "Hazard" is pushed down the switch is in the turn signal position. Its center terminal also has 2 wires one is yellow/black and the other is light blue/white. The mating contact has a gray wire.

Hope this helps.

I could send you this switch if you want to try it.
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