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Discussion Starter · #1 · (Edited)
Hi,

I'm having some issues with the horn and flasher-relay on my '75 Alfa GT Junior.

The flasher relay is the can-type with 3 pins (X,L,P). It is the only thing connected to fuse 3 (8A). Yet the fuse keeps blowing out, sometimes right after we insert it, sometimes it takes a couple of minutes (the indicators do work during these minutes...) I've disconnected the flasher-relay, but don't really know how to test it. I've put an ohm-meter between the pins L and X and measure about 25 Ohms (this should be the control-circuit). The other pins are open contacts.

Anyone know if that's an indication that the relay is bad? I would like to test the relay with a 12V source, but I think i'll just short it as there is no load connected to it (it's out of the car).

Also the horns stopped working, I have an original FIAM relay block in the engine-compartiment (3 pin), that runs a single cable to the horns, so I'm guessing that's the relay driving them. I tried to short the horn-button on the steering wheel by connecting the pin on the relay directly to the ground, but the relay doesn't click and the horns don't work. Anyone know if there's another way these can be tested? The horns work when directly connected to 12V.

Thx !

EDIT: Nevermind the horn-relay issue, it seems I don't have a solid 12V powersource connected to that relay.
 

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The flasher relay is the can-type with 3 pins (X,L,P). It is the only thing connected to fuse 3 (8A). Yet the fuse keeps blowing out,...
I doubt your flasher relay is the problem. The flasher isn't connected to ground so it is hard to picture what could go wrong inside the flasher that would cause a short to ground (which is what blows fuses).

My guess is that something downstream from the flasher is bad: one of your four turn signal sockets, the wires to the sockets, the turn signal switch or the emergency flasher switch. I would start by examining each of the sockets.
 

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Discussion Starter · #3 ·
I've just made sure the horn-relay has solid 12V power.
Yet the horn still isn't working.
Does anyone know where the black cable going into the steeringbox goes (the one that should be coming from the horn-button)?
I can't seem to find its connection point on the steering rack.
 

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Discussion Starter · #4 · (Edited)
I doubt your flasher relay is the problem. The flasher isn't connected to ground so it is hard to picture what could go wrong inside the flasher that would cause a short to ground (which is what blows fuses).

My guess is that something downstream from the flasher is bad: one of your four turn signal sockets, the wires to the sockets, the turn signal switch or the emergency flasher switch. I would start by examining each of the sockets.
I tried measuring the ohms on both the flasher circuits (to ground). They both read about 1.5 ohms, which I think is a short. That would mean there's a short in both the circuits.

Also the blue wire coming from the dashboard indicator-lights measures about 1.5 ohm, which would also mean a short.

I hate wiring an old car...

EDIT: The blue wire for the dash indicator light measures around 6 ohms now.
Both left and right circuit for indicators measure 1.5-2 ohms. I've measured them on the rear indicators and they both read the same.
 

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Discussion Starter · #5 ·
Allright,

All issues seem to be fixed.

The black wire coming from the FIAM relay goes into the steering box and should run all the way up to the plastic cap on the steering wheel (where it is then connected to a spade)
Mine had apparently snapped halfway. I've put in a fresh cable and the horns started working again!

The fuse-blowing flasher relay also seems to behave for the moment.
I cut away some obsolete and useless cables and put 2 new spade connectors on the flasher-circuit connectors under the steering column
So far everything seems to be working, let's hope it stays that way... :)

Anyways, thanks for the feedback!
 
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