Coolant tempepature gauge question

[Mr. Y]

Hello. My stock coolant gauge (on '87T) doesn't working (it always shows very cold temp), so I have 2 questions:
1). Where is located sender for this gauge? (I saw picture with sensors here, but cant find it now)
2). Have you any ideas, what causes that trouble?

Thank you

 

[IJ.]

Could be anything broken wire faulty gauge faulty sender.

 

[Mr. Y]

Thank you.
Another question: can I check wiring by grounding wire, that goes on sender? I suppose, that if wiring is good, gauge on the dash should show overheat, when grounding wire - am I right?

 

[Bishop92t]

http://www.cygnusx1.net/supra/library/TSRM/be/BE_041.html