Headlights gone and PO wiring

[Andyblahblah]

Hi All,
I'm sure the answer exists, but while I'm searching (some more) I figured someone would know offhand.

I recently got a 75 1.8 and the PO did a number on the wiring. The center console is gone, God-knows-what wiring is stuffed up under the dash and there seem to be a variety of recent inline fuses and relays in the cluster of wiring jammed behind the gauges and steering wheel.

I ignored all that and tooted around the neighborhood for a few days waiting for parts, but after some (literal) poking around the loom to get an idea of the damage, the headlights that worked fine suddenly ceased to do so. More poking has gotten me nowhere. I'm sure it's something stupid I'm missing.

Here are the symptoms:
- light switch on = green light on in odo, rear and side marker lights, but no HL (and no power at bulb itself)
- high beam switch on = no change, no blue highbeam indicator
- light switch toggled on/off = clicking black relays w/ some heavier gauge wire behind the fusebox, but oddly NO power at any of the terminals on either of these 2 relays, I only assumed there would be.
- traced what I assume to be the power in to these relays to a loom waaaay in there (heavier gauge red wire), but haven't dug so deep yet.
- no lights at gauges either, though not sure if related.
- blinkers work
- the inline fuses under the dash (from ignition..?) seem to be ok.

I haven't tested power at the acual light switch itself yet, and all fuses are intact - except the next-to-last one (#2 from left) which was missing. I tried putting a 5amp back in, it starts to get hot/unhappy and I pull it back out - I understand that one to be the heater and wipers.

There are also a number of loose connections and missing fuses/relays in the engine bay near the driver side wheel, but again the lights did work before. The correct wiring diagram would help me identify those orphans, but I don't think they're to blame here. I like to think he 'streamlined' the electrics, but as the wiper motor is also AWOL, I assume I'll have to dive into my new Italian friend's wiring more so than I'd hoped.

I've wired a few cars and many motos, but this is the latest model car I've worked on (heh). I found the wiring diagram for the 75 from Artique, but it's pretty inscrutable - I understand 74 -76 are all different in key ways..? I also have a Haynes, but the diagram is in the supplement as the UK version. I'm hoping someone can just tell me where to hit the car to fix it. Meanwhile, I'll be zooming in on the Artique diagram to trace tiny lines.

[RRoller123]

Cleaning up the ground pods on the inside of each of the front fender wells is always a good place to start. "It's always the grounds" as they say.

[70spider]

When I got my Spider the PO had done some creative wiring and I found this: http://www.artigue.com/fiat/. It has proved to be invaluable. The wiring diagrams are color coated and easy to read.

[Andyblahblah]

Thanks guys - as I said, I found the Artique diagrams, but my understanding was the 75 was different. Maybe not.

Anyway, I printed large versions of the 74 and will trace to see what's different. Quirky little thing.

[Andyblahblah]

Update: FWIW for the next guy, the PO added a relay to each of the headlights, which were powered by a red wire with an inline fuse.

Somehow, one of the courtesy lights under the dash is also in that series, so when I tried to plug in a replacement bulb, that blew the inline fuse. That's another job on the list for later, because I have lights now.

Side note - it seems insane to me that the headlights are on their own, independent fuses.

[707kevin]

I've got a 75 also.
the 76/77 diagrams are close enough to to figure it out. not every wire color is correct, but enough are that you can get by.

[DieselSpider]

Update: FWIW for the next guy, the PO added a relay to each of the headlights, which were powered by a red wire with an inline fuse.

Somehow, one of the courtesy lights under the dash is also in that series, so when I tried to plug in a replacement bulb, that blew the inline fuse. That's another job on the list for later, because I have lights now.

Side note - it seems insane to me that the headlights are on their own, independent fuses.

There are four 8 amp fuses in the stock configuration to protect and isolate the headlamp circuits so if one blows you will only lose one high or low beam. 2 more 8 amp fuses protect the left and right running lights. They set it up so one fuse would not shut down all your lights leaving you blind and invisible.

[Andyblahblah]

There are four 8 amp fuses in the stock configuration to protect and isolate the headlamp circuits so if one blows you will only lose one high or low beam. 2 more 8 amp fuses protect the left and right running lights. They set it up so one fuse would not shut down all your lights leaving you blind and invisible.

*thumbs up*

[RRoller123]

+1

Hmmmm.... his implies that I should split my 2 relays (one for Low, one for High) into 4 relays: 1 for each of the Left and Right Low and High beams...

Food for thought.

I actually had the high beams blow out once, tooling along at a brisk pace on a dark back road after I first installed the relays (because I chose a too small fuse value) but I still had the Low beams.

Pete