1981 Spider electrical diagram

[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]

Check out the library section at mirafiori.com for electrical diagrams and a wealth of other info.

[18Fiatsandcounting]

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]

..... 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.

[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]

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