Hazard flasher vs turn signal flasher on a Fiat 850

Fiat4Fun

Fiat4Fun

True Classic
So on my 1971 850 spider, my turn signals work, but my hazards do not. I see the old screw terminal flasher unit under the dash by the steering column. Checked the wiring diagram, and confirmed the switch is good ( swapped it with another). On the wiring diagram, it shows the red wire going to "flasher hazard warning signal". It looks like it has 4-5 wires on it....Not sure where that is, and wondering if it got unplugged when I painted the car. The weird thing is, when I flip the hazard switch on when the turn signals are working, they stop.......

Any thoughts would be appreciated.
Thanks
Bob
 
Do you have the 850 electrical diagnosis book?

I don’t know if I scanned it or if someone else did. I will have a look. I can scan mine as it is a loose leaf book and make it available. Let me know.

Karl
 
Even though the wiring on old Fiats is pretty basic compared to modern vehicles, it can still take quite a while to trace the wiring and figure out what goes where and to diagnose problems. A wiring diagram and a multimeter should be all the tools you need. I would methodically trace the relevant wires from end to the other using the multimeter and compare to a diagram.

Did you disconnect connections at the front turn indicator lights or tail lights during the paint process? If yes, perhaps you got the parking and turn signal connections swapped at one or more of the lamps? Check to see that it is the brighter filament in each bulb (dual filament) that is flashing by removing the lenses. The resistance of the turn and parking lights is different and could cause the flasher to not work correctly. When flashers are turned on, there are 4 bulbs that are energized and are twice the resistance compared to when 2 bulbs are energized when turn signals are activated.

There's always the chance that the flasher isn't working well and might need replacing, especially if it's an old electro-mechanical one. These have a bimetallic element that gets heated by a wire wound around it and bends it and opens/closes the contacts.

My factory and Haynes wiring diagrams don't show a red wire but they don't show the hazard switch. The flasher has 3 connections, one is power, one is to the indicator light on the dash and other is the signal to the turn/flasher lights front & rear. There's also a ground connection that you might want to check.
 
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I have the printed version for the X1/9, but never seen the 850 electrical guide, Karl thank you. I will look through that. I went through my wiring diagrams, and need to check the power coming in through the courtesy light under the dash. It looks like the flasher gets power from there when you hit the switch. Looks like a bit a variation between the 1971 and 1972 version. The 1973 version is way different from the wiring diagrams that I have. Will play with it tonight and let you know.
 
The 850 Electrical Diagnosis Guide is available right now at Mira, you will need to sign up but there are many benefits to being a member there as well.

https://www.mirafiori.com/forum/viewtopic.php?f=125&t=99101

I will have a look for Spider wiring diagrams. I do have the factory manual which has a US Spider diagram. I can photograph it today and scan it tomorrow if that would help.
 
Thanks for the note, I have a bunch of wiring diagrams for the 850, and Karl sent me the Electrical Diagnosis link, so thank you. Many years ago I was using mirafiori forum, but it was not very active. Is it more active now with rear engine Fiats? Might see if my old user name and password works......
 
Here is the 850 Trouble Shooting Aid and two versions of the Spider wiring diagram.

I will replace them with scans tomorrow if I can.
 

Attachments

  • 850 Electrical Troubleshooting Aid.pdf
    3.8 MB · Views: 162
  • 850 Spider Wiring 2.pdf
    5.5 MB · Views: 175
  • 850 Spider Wiring 1.pdf
    4.6 MB · Views: 196
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Thanks for all the help, and all the cool downloads. Is there way to save these on this forum, like a sticky, for the next group of 850 owners?
Turned out that one of the white wires going to the drivers under dash courtesy light had broke underneath the black rubber protector. I took it off, sobered it onto a new spade lug, and whamo, my hazards worked again. Everything is working as it should with the one exception. When I turn on the courtesy light switch on the dash, the key buzzer goes off. Yes, I did but the fuse back in when testing the electrical system and got to hear that annoying sound. Not a big deal, but with all the cool stuff you all shared, I might figure that one out too....
Thanks again
 
I think the old 850 stuff is getting harder for people to find. It would be cool if we could archive stuff that would be helpful for the next bunch of decades of rear engine folks...... I know I use the Jeep forums archives a bunch when I run across a issue. Not sure how to go about getting that set up.......
 
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