Pontiac Repair: 1988 Pontiac Firebird Temp Gauge, pontiac firebird, coolant temp

Question
Hello.  I have a 1988 Pontiac Firebird 5.0 Litre V8 TBI automatic transmission 2-door hatchback t-roof that used to belong to my mother.  The car sat in her garage for over 7 years.  It runs great!  However, the 'ENGINE TEMP GAUGE' on the dash DOES NOT WORK.  My mother claims that her mechanic friend (who isn't around anymore) forgot to connect some cable (engine coolant temp sensor or sender or something like that) she can't remember.  Where is the 'engine temp sender or sensor' cable located?  The Pontiac Service people claim that there's one on top of the front of the engine block next to the A/C and the other one might be on the driver's side of the engine block on the cylinder head or intake manifold or even on the radiator.  They want $300 just for looking at the car (diagnostics).  Could you help?
Thanks - nickita

Answer
well yes there should be a brass like sending unit in the top wateer port, and one i think on that one it is located on the right side half way back on the side of the block behind the exhaust. you can cheat and go to an autozone and look at one of the chiltons books to make sure, or go to the barnes and noble and see it in the book as well easier to look at the picture and me trying to tell you..