Mystery inline fuse

[spidernut]

I needed to reconnect my speedometer cable and found an inline fuse behind the instrument cluster that was blown. Everything worked prior to replacing the fuse and everything works after replacing the fuse. I can't find the fuse on the wiring diagrams either.

Here's what it is: 16 amp inline fuse, white wire with a black stripe down the length of the wire. Both ends go into the main wiring harnesses, so I can't trace the other end.

Anyone know what it belongs to?

[GeorgeT]

Cigarette lighter?

[azruss]

if you car is FI, then the fuse may be in-line with the dual relay for the fuel pump

[narfire]

Have you Brad's wiring diagrams? Take a look there.

[spidernut]

I have Brad's wiring diagram...I don't see the fuse on any of the charts. I also have an original wiring diagram...also not on the charts. The cig lighter works.

It is EFI, but everything seems to run right and it just flew through the emissions test with really, really low emissions readings.

[rlux4]

Does it look like a factory fuse holder? I only know of two inline fuses behind the main fuse panel, one on a red wire for the lighter and the other on a brown with white stripe wire for the fuel pump side of the dual relay.
Ron

[spidernut]

It is definitely a factory wire and fuse holder. Today, I'm going to spend some time today trying to figure it out.

When I purchased the car, I found that it had several wiring modifications for an ignition defeat system, radio, splices for unknown reasons, etc., which rendered many interior components no longer working. I spent hours pouring over schematics and getting everything back up to factory configuration and operating properly except the light on the console that is for the fiber optics.

The only thing left to figure out is this inline fuse that enters and exists the wiring harness at each end, and the same colored wire hanging loose under the dash near the clutch pedal. That end of it goes into another wiring harness. Of course, the end is cut off and hanging loose.

Since it has the black stripe, it is undoubtedly a ground for something...the question remains...for what? I'm hoping to figure that out once and for all today.

[rlux4]

I have to work today while you get to have all the fun! What could be better than tracing wires up behind the dash?
Ron

[courtenay]

What could be better than tracing wires up behind the dash?
Ron

How about pulling your fingernails out with a pair of pliers??

[spider2081]

I don't know what the fuse is.
It might help to know when the fuse has power going to it. Is it hot all the time or is it hot in start and run positions only of the ignition switch. You might want to check with a trouble light and see when the fuse has 12 volts on it.
One other thought many of the grounds in the Fiat are white with a black stripe. I think the rear marker plate light power wires are also White with a black stripe. I can't recall ever seeing a fused ground wire on a Fiat. I think this wire is a power source for something.

[rlux4]

"How about pulling your fingernails out with a pair of pliers??
OK, but only slightly.
This cracked me up Bruce!
Ron

[Zulu]

I believe the "auxiliary" power socket has an inline fuse. It is mounted underneath the dash on the drivers side, right next to the steering bracket. It was used originally for a flashlight-type thing on an extension, but only one or two are known to still exist. I don't know if Fiat ever stopped putting them in cars, but my dad's '78 has it.

It would make sense if that's what it is, because I'm sure you don't use it and wouldn't notice if it wasn't working.

Zulu

[GeorgeT]

I believe the "auxiliary" power socket has an inline fuse. It is mounted underneath the dash on the drivers side, right next to the steering bracket. It was used originally for a flashlight-type thing on an extension, but only one or two are known to still exist. I don't know if Fiat ever stopped putting them in cars, but my dad's '78 has it.

It would make sense if that's what it is, because I'm sure you don't use it and wouldn't notice if it wasn't working.

Zulu

The Aux. socket is connected to fuse #9 according to Brad Artigue's diagrams.

[Zulu]

On my car, on the actual car and not the wiring diagram, a black wire goes from fuse 1 to an inline fuse. A wire then exits that fuse to the aux socket. I guess they switched things up in later years.

[Gerry]

My cigar lighter in My 79 Spider was dead. Here’s how I fixed it...
The in line fuse is underneath the dash on the left side of the steering column. The fuse was blown and was a 16 amp which is incorrect. I replaced it with a proper 8 Amp. I then took a Dremel and cleaned the socket and heating element/surrounding area properly. I bent the two prongs inside the socket in so that when pushed in the lighter holds.
All works fine now.