Triumph Repair: Instrument Voltage Stabilizer, triumph spitfire 1500, voltage stabilizer

Question
QUESTION: The vehicle is a 1974, Triumph Spitfire 1500. On the back of the speedometer is the Instrument Voltage Stabilizer. The voltage stabilizer has 4 connections on it. One set of 2 connectors has the letter "I" (or a #1) by it.  The other set of 2 connectors has a letter "B" by it.

My question is, which wires connect to which of the 4 connectors?

ANSWER: Hi George,
"B" gets the green power wire and "I" gets the light green wire for the two gauges.
Howard

---------- FOLLOW-UP ----------

QUESTION: Howard,

Much thanks for your quick reply.

Of the tangle of wires hanging out of the panel those two wires apparently didn't get labeled. If the 'All Experts' protocol allows me to ask another follow-up question about a different panel item, I will present it now.

Question regarding the Panel Light Rheostat:  The knurled knob, obviously designed to be turned, as one would expect to do when brightening or dimming the lights, is fitted onto a hex shaft that goes through a hex hole at the outer end of the threaded portion of the unit. That threaded portion does not rotate.  

The shaft does not move in and out.

Question: How can a knob turn a hex shaft that goes through a hex hole?  Since I see no way for it to do that, and, the shaft does not move in and out, I am at a complete loss as to how the knob can do anything.  

It's been so long since I drove it I don't remember if it worked at that time.

P.S. Where & how do I rate your answers?

Thanks again, Harold.
George  

Answer
Hi George,
I am Howard not Harold, but you can ask as many questions as you want. As I remember all of the light rheostats that I ever seen on any of the British cars rotated. If the switch has a couple of red wires on one pin and some red w/white tracers on another pin and is large in diameter, than it may be a rheostat but I don't remember any of the older Spitfires having a light rheostat on them. The control knob will be large in diameter also as none had small knobs. Most of the rheostats were open in the back and you could see the coil laid out in a circle and the runner that went on it. Also the back base was made of ceramic and no plastic.
Howard