> 1970 SPL311: There is a little box with two pins, one marked ign, screwed
> to the right side of the steering column... Someone on the list said that it
> was a voltage regulator for the gas and temp gauges.
Yes, it is. Note there's actually three connections: It grounds thru the
mounting screw. If it is not firmly screwed down, it doesn't do its job.
> Question: What does it protect?
It doesn't protect anything. It makes the fuel and temp gauges properly
register.
The gauges only need/want about 6 volts to properly register. If you
bypass this box they'll get the full 12 volts all the time (this is what
happens if it's not screwed dow, BTW). The gauges will peg and will
probably be very unhappy after a while of this.
Note that this box is more than a voltage regulator - it is also a
temperature compensating device. The gauges work via bimetal
strips that are heated by the flow of electrical current. A car can
move between sitting in freezing weather and parked in the desert
sun. In order for the gauges to remain accurate across that sort of heat
range, some sort of compensation needs to be added, and this box
does that. Since it too is bimetallic, it too is affected by ambient
temperature swings. It reacts opposite of the gauges, keeping
things relatively accurate.
-- John
John F Sandhoff sandhoff@csus.edu Sacramento, CA
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