no voltage at black wire

[dulcimerbob]

I have no voltage at the black wire on the switch . Any ideas?

[azruss]

do you have a schematic for your car. Many are available thru brad artigue. You need to find 2 pieces of information. first is where the black wire is coming from and is it supposed to be the source of 12v for the ignition. 2nd is to see if the location on the ignition is right. other who have switched to a new ignition should be able to tell you if any of the contact locations have been altered from the original. There are a few inline fuses as well to contend with and it could be the black wire has one that is blown. I've never messed with a 76 so i cant be anymore specific and you cant alway trust Fiat to have used the proper color code for all the wires. My guess is if you had it working before with the wiring as is, you have a blown inline fuse someplace.

[hybenz]

Check the fuse, fuse link or circuit breaker that protects the circuit. Also try to check the power relay that supplies voltage to the circuit. Though if there is a blown fuse replacing tit may restore power temporarily, but unless the underlying cause for the overload is found and corrected, your "fix" probably will not last. Blown inline fuse is the same reason here on car problems,similar situation..

[courtenay]

This may sound dumb - particularly coming from someone who knows so little about this stuff - but aren't black wires usually ground connections? If so, there shouldn't be any power at the ground terminal.

[spider2081]

Black is often the color used for ground connections in DC circuits but not always. Fiat does not adhere to the red is positive and black is negative color codes.
I a m not sure of the connections for your car. I have a diagram that shows the heavy black wire at the ignition switch connects to the battery terminal of the alternator. This would make the wire hot all the time as the alternators battery connection connects to the starter solenoid on the same post as the battery positive. There are no fuses in the path of the wire in my diagram.