Are these electrical problems related (fuel and ambient temp)
 

Recently, I noticed my fuel gauge intermittently reading full while I had half a tank, and my ambient temperature readout on the overhead console was erratically reading low by about 40º. Sometimes these would be corrected (temporarily) by switching the truck off and back on. Are these two issues related by a single electrical glitch? I know my truck had some moisture in it over the winter, probably through the cab lights. I've fixed that, but am still stuck with this electrical gremlin. I find it suspicious that these two electrical issues popped up at the same time after the moisture issue, leading me to think there must be a unifying diagnosis. Any ideas? Thanks.

Did you get this solved?
I had a similar problem and changing the electrical switch under the column that is activated by turning the key definitely helped.

No, haven't had another look at it yet. But thanks for the lead.

From my experience, yes, they are related. When the in tank fuel sending unit on the '99 went out and was permanently stuck on "Full", the ambient temp reading on the overhead console display showed temps that were significantly lower than outside ambient temps in both Fahrenheit and Celsius. Replacing the fuel sending unit fixed the problem.

As a follow up, the problem seems to have corrected itself. I sealed my overhead cab lights with gobs of silicone, and left the truck in the sun for a few days with the windows rolled up. I suspect it was a moisture related electrical issue from the leaking cab lights, hopefully now dried up for good.