84 c20 alternator excite wire (brown)

Folks, we have upgraded the alternator in my C 20. We have traded the SI 12 for a newer CS 130d.

We are getting sporadic charging, as verified with a VOM at the battery with the engine running.

Trying to figure out where the resistance is in the excitation line, since my truck has the gauges. In the trucks with warning lights, the light is the resistance. How is the same resistance provided with gauges ?

Any guidance ? GM manual stops at the bulkhead, and any other reference I have examined is generally generic in nature.

Thanks

HammerWerf

I would think a schematic of the charging circuit would help you. I don't know what a SI 12 or a CS 130d are but any resistance would be from the wire in the rotor, the excitation coils. The idiot light in that setup is only an indicator. Checking voltage at the battery should show sporadic charging as the electrical system loads change (a/c on, headlights, heater blower, etc.). I have an 84 GMC C20 suburban with diesel and gauges. I would like to know what a SI 12 and a CS 130d are. Thanks. Okay. I did a search here on the alternators and found a bunch of good info about those types and more. No need to respond to my question about info on them.

If you put a "194" bulb inline of the brown exciter wire you will have the correct resistance for the alternator. Contact Mark at MADelectrical. GREAT guy and knows his stuff about the "CS" alternators.