1997 Tracker - Temp Gauge on Cold

[TrackerLux]

New Tracker owner.  

Loving all the info from the Trackick crew.  

Driving the Tracker last night.  I noted the temp coming up while on surface streets heading toward the freeway.  As I was cruising on the freeway I looked at the fuel gauge and felt like it had gone down to much for the trip that I had done.  Scanned the dash and noticed that the temp gauge was no longer in the middle of H and C but buried on Cold.  

It was running smooth on the freeway and surface streets.  There was one instance that I came to a stop and the needle on the temp gauge seemed to jump back to the middle and then quickly fell back to cold.  Almost seemed like some sort of a vacuum issue?  This only happened once in many stops.

Hoping the community can give me some repair steps.  As my only thoughts are thermostat and or temp sending unit?

Thanks in advance!

it is real simple this device (guage)
a gauge,
a wire (1)
and sensor.

if the othermeters works then power to the cluster is ok 12vdc ok. 
the most common failure is the sensor is bad or the clip on the wire on the sensors is rusty.  it is old so rust happens big time on old cars.

the sensor is on the thermostat housing, dead front pointing front. and 1 wire, if gauge id dead, wiggle that connector even use pliers to make it tighter.


here  are the tests both hot  and cold.

https://fixkick.com/sensors/tests/Guage-...-test.html

Thank you for the reply FixKick.  Really appreciate the time and effort you have put in to keeping these vehicles on the road.  

I did take some pics but they were to big to upload.  In taking pics for the forum - I checked that connection on that front sending unit.  Just as you mentioned the connector that attaches to the blade failed.  When I removed it to check for corrosion I found that it was already in several pieces.  Totally annoying.  

Sidebar - this Tracker has the timing set to 4pm.  It runs decent but I will be using all your knowledge to set it back to stock.