Multiple dash electrical problems

[btolman]

I have an 83 pininfarina that recently went through a rather extensive restoration. Until recently no significant
electrical issues . Then the other day I lost my oil pressure gauge reading although the oil pressure light works fine. The sending unit was leaking so I replaced it with a new one. Solved the leaking but the gauge still doesn't work. Then I lost my dash lights, side lights and tail lights . The alternator light stays on when the engine is running, the tach reads about 300 rpm's even though the idle seems normal. One turn signal works the other doesn't. And if that isn't enough when I remove the key from the ignition the engine continues to run! I have checked the grounds in the engine compartment as well as the connections around the battery in the trunk. The number 12, 8 amp fuse on the far left of the fuse block was blown and I have 12 volts on each side of the fuse with the fuse removed. Last but nor least the horn works only intermittently.
I appreciate any advice.
Thank you

[GeorgeT]

Go through the electrical system and clean each ground and connector and coat with dielectric grease before reconnecting. 90+% of the electrical problems are caused by corroded grounds and connectors.

[4uall]

+10 for cleaning grounds etc

http://www.fiatspider.com/f08/viewtopic.php?f=6&t=22586

[narfire]

I found cleaning the contacts on the fuse bus helped as well. A dremel with the small wire brush worked great.

[btolman]

Thank you, where would I begin to identify location of all grounds in electrical system?
Bruce

[TX82FIAT]

I had an 83' in the 90's that had the multiple dash issues. After taking sandpaper and dialectric grease to grounding points I then realized I had neglected the two largest grounds. 1. The battery cable ground. Not sure what length you need as I have not fiddled with the battery behind the passenger wheel well in some years. A good, clean, new battery ground will help. 2. The grounding strap under the engine should be clean and tightly secured. 3. There is a grounding pod under the dash that I'm not sure you mentioned. This ground is typically in good shape because it is inside the vehicle. I'd clean that one as well if you have not already.

[4uall]

Thank you, where would I begin to identify location of all grounds in electrical system?
Bruce

This will help

http://www.fiatspider.com/f08/viewtopic ... it=+ground

[btolman]

I have checked all the grounds that I can find and still have the issue of the engine continuing to run with the key out of the ignition. Even if I disconnect the ignition from the electrical system the engine keeps going. I suspect that I have a feedback issue that keeps supplying the coil with power. Once in a while if I turn the parking light switch on the steering wheel to one side or the other this will kill the engine but if I restart the engine I am back to the same issue. Disconnecting the negative battery lead results in the engine continuing to run, but the rpm's increase.
Appreciate any additional thoughts.
Btolman

[spider2081]

What happens if you disconnect the field wire from the alternator. I think its possible for the voltage regulator to fail and back feed voltage to the power in "run" position of the ignition switch.

[btolman]

Thank you for the advice, I am not particularly techno savvy about electricial terminology. How do I determine the field wire on the alternator? Is the voltage physically close to the alternator? If what you suggest is true, would the engine continue to run when I remove the key from the ignition as it does now? I appreciate your help.
Btolman

[btolman]

I meant to say is the voltage regulator located physically close to the alternator?

[westy64]

I meant to say is the voltage regulator located physically close to the alternator?

very close, being inside, on a 83 spider.

[spider2081]

I believe your alternator has 3 electrical connections on the back of it. One has a nut holding on wires with ring terminals. That is the alternator output that charges the battery. The others are push on "spade" terminals.
I think your field wire is "black with a violet trace" If you pull on the wire it will come out of the alternator. leave it out and see if the car starts and shuts off. Of course the alternator and battery warning light will not work with it out.
The other "push terminal" wire is from the radio filter capacitor mounted on the back of the alternator. Leave this one alone.
Let us know what you find.

[btolman]

Dear spider 2081: when I unplug the wire (spade connector) that goes from the alternator and disappears into the wiring harness and start the car, it turns off immediately when I turn off the ignition.if I plug the wire back into the alternator then the engine won't shut off. Interestingly enough, with the ignition off and battery connected, the seatbelt indicator light glows faintly. With the parking lights on I noticed that the left rear marker light was not working. The bulb is good because it works on the other marker light and I measured 9.8 volts coming from the socket and yet the bulb wouldn't not light up. The right rear marker light measures about 11.5 volts at the same time. And then suddenly the left rear marker light started working and the voltage measured 11.5 volts, the same as the right side.
I don't know if I mentioned that since this electrical issue started, the engine runs a little rough and the tach indicates about 500 rpm instead of the normal 800-1000 rpm.
Thank you for your continued help.
Btolman

[narfire]

Welcome to the electrical nuances of the Fiat Spider....