1981 Spider electrical diagram

Gotta love that wiring . . .
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Epdiver
Posts: 1
Joined: Sat Mar 21, 2020 8:27 am
Your car is a: 1981 Fiat Spider 2000

1981 Spider electrical diagram

Post by Epdiver »

My car starts running rough (or dies) when I turn on the headlights. I assume this means I have a pretty bad ground. I'm not an electrical guy so I thought my first step would be to get a wiring diagram. I'm open to any suggestions anyone might have. Thanks.
PaulC
Patron 2022
Patron 2022
Posts: 265
Joined: Tue Oct 31, 2017 5:04 pm
Your car is a: 1979 Fiat Spider 2000
Location: Maine

Re: 1981 Spider electrical diagram

Post by PaulC »

Check out the library section at mirafiori.com for electrical diagrams and a wealth of other info.
18Fiatsandcounting
Posts: 3799
Joined: Fri Mar 15, 2019 11:23 pm
Your car is a: 1969 and 1971 124 spiders
Location: San Francisco Bay Area

Re: 1981 Spider electrical diagram

Post by 18Fiatsandcounting »

Epdiver wrote:My car starts running rough (or dies) when I turn on the headlights.
It could be an electrical issue, but I've also seen a few cars over the years (not just Fiats) where turning on the headlights put enough of a drag on a weak idle to cause the engine to stumble, or at least slow down a bit. Causes of this could be a marginal battery (or connections), or an idle speed that is set too low.

So, before diving into the challenging electrical system, check your battery and connections, and make sure the idle is set to where it should be. Maybe turn it up a bit, like 900 or 1000 rpm, just to test if this helps.

-Bryan
76was124
Patron 2019
Patron 2019
Posts: 620
Joined: Sun May 16, 2010 4:43 pm
Your car is a: 1981 Spider 2000
Location: Detroit Area

Re: 1981 Spider electrical diagram

Post by 76was124 »

18Fiatsandcounting wrote:
Epdiver wrote:..... Causes of this could be a marginal battery (or connections)......
-Bryan
I agree with Bryan, first have battery and alternator tested. Could be either, neither or both. Local national autoparts starts will usually do this type of test for free.
Current 81 Spider 2000
Previous 76 Spider
rridge
Posts: 162
Joined: Thu Aug 10, 2006 11:59 am
Your car is a: 1981 Turbo Spider

Re: 1981 Spider electrical diagram

Post by rridge »

The headlights are grounded to "pods" multi-tabbed cad-plated grounding terminals screwed to the inner fenders in the engine compartment just behind the headlight. They pickup a fair amount of moisture and benefit from occasional corrosion cleanup.

For an '81 Spider the best electrical reference is the factory's own Spider2000 electrical diagnostic manual. You can download a PDF copy from the mirafiori.com forum's library section once you sign on as a member. The headlight chapter begins on p.26 and includes a diagram of all the lighting circuits, identification and descriptions of each component and pictures to help you locate them.
GeorgeT
Posts: 379
Joined: Thu Feb 16, 2012 12:41 pm
Your car is a: 1982 Fiat 124 Spider

Re: 1981 Spider electrical diagram

Post by GeorgeT »

Had this issue with my '82 and it was a failing alternator.
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