Irratic Temperature Gauge Readings

I think that your gauge is OK, but the connection of the wire to the gauge has become slightly corroded over time.  Crawl under the dash and find that lead again and pull it off of the tab on the back of the gauge and replace it five or six times to clean up the push on connectors and the tab it pushes on to, and see if that cures it.  

Be aware that the wire might come loose from the crimped on connector on the end of the wire and that might be your problem, too.  In that case, take it to a shop that can crimp on a new connector end and that should certainly solve your problem as it was failing anyway.

Good luck!

Gordon

The Speedstah Guy from Grafton

Thank you Gordon.  Having just replaced my master cylinder and becoming very familiar with the alligator move of getting under the dash a few weekends back, I guess its back to it.  I'll see if I'm lucky enough to loosen the gauge and pull it out of the dash to possibly attack the wire attachments from the drivers seat.

Thanks for the suggestion.

Grant

You should be able to get at the connection without pulling the gauge.

gn

If you disconnect the wire on the sender (not on the gauge), what does the gauge read? If you now touch that wire to ground, what does the gauge read?

Most common VDO temp gauges will read cold when disconnected (high resistance) and read hot when grounded (low resistance). So unless your gauge works in the other direction, which I suppose is possible, its odd that a loose or corroded terminal would cause it to read hotter.