Case 580SK Electrical Problem

Ditchdigger67 Post #13 maybe
There are three wires to alt
> Big red wire power to batteries = That was easy
> one wire plugs in = Tachometer
> one small wire bolts on = power to excite and start the alt charging --- With ignition off no power - ignition on should be minimum of 10 volts

The dash and wiring on these SK units was not great. The W wire was always a problem. The dash in those macines are easy to trace the path, Use a spade connector and crimp it on a length of wire and plug it into the W socket at alternator. Run the wire along the RH frame rail and into the cab up to the dash area. Unplug the dash connector, the wire from the W terminal is the same color from the alternator to the plug green/yellow I think. Cut the wire 6 or 8 inches from plug and solder in the new wire. Noiw take some fine emery cloth or sand paper and make sure the connectors at dash are good and clean. This should solve the problem. Another cause of a tach bouncing is if you have the cold start package (dual battery) and one of the batteries is dead or almost dead it will cause an erratic tach.

Thanks!