quote:Detom, does the temperature appear to drop if the engine speed drops below the point where the alternator stops charging?
No that doesn't seem to do it, it is only when I turn on another accesory, and then it it just drops to what I am thinking is a true reading. I am betting that a resistor is going out, and that failure mode is the least common. Usualy when a resistor goes out it goes straight to an open circuit, which would be a zero reading at all times. I have seen this a few times in my career as an engineer where the resistor will only partialy fail, but it is rare as hens teeth.
I don't know if I really want to tear into this problem or not. I can tell for certain it isn't really overheating. It may just be something I will live with until I restore the car at which time I am going all new harness anyway. It just goes to re-enforce my feelings about the accuracy of 30+ year old gauges. They are mearly friendly suggestions and not true indicators.
