<BLOCKQUOTE>quote:</font><HR>Originally posted by Skye:
You mean the whole temp guage/gas guage thing?
<HR></BLOCKQUOTE>
The temp guage is separate from the gas-gauge. While the temp sender may be readily-available, the gauge itself will take some hunting to track down.
It does indeed contain a crude "voltage regulator", which really should be called a "bimetallic temperature averager", as all it does is alternately turn on and off the 12V(+) feed to each of the other gauges (~1cycle/second), so the bimetallic arms in those gauges gets fed more or less an average of 5V(+) (which is to say that they get about as warm, and bend as much, as if they were fed a constant 5V(+)). This is why the earlier FSJ gauges take a while to "warm-up", especially in cold weather, why they are so slow to react to changes, why they read differently in cold weather than in warm, and why they "pulse" ever so slightly under normal operating conditions.
The voltage regulator itself uses such a bimetallic arm. The amount of heat the bimetallic arms in the other gauges see depends on the resistance from the senders, which is affected by the resistance of the intervening wires and connectors. When you think about it, it's amazing that any gauges provide any readings at all.
Oh, and as for not working, a break in the wires of the voltage regulator can cause it to not function, as can a problem with the slip-on noise-suppressor that jumpers two pins on the back of the printed circuit board on the instrument cluster.
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Bob Barry
<UL TYPE=SQUARE>* '78 Cherokee 4-door
* '88 Grand Wagoneer[/list]
http://studentweb.providence.edu/~rbarry/wheels/