coolant sensor fault code

[Beachbum3478]

i just checked the fault codes for my 88 lebaron gts 2.2 turbo auto because i just undid a vacuum line while the engine was on and it gave a code 13 like usally, but while i was reading, a code 22 came out. i was like wtf. so i found what it was and it said the coolant temp sensor voltage to high or to low. the reason that i could see it storing this code is when i had it unplugged and tried to start the engine, is that all it was?

[Beachbum3478]

i just turned the key to on and the coolant temp guage is still on the fourth bar on my digital dash. so with it still on i unplugged the two wire coolant sensor plug, but nothing happened on the gauge, it stayed the same. so then i unplugged the one wire plug that is on the head right in front, to the right of the the a/c compressor, well after i unplugged that the gauge dropped down to one bar. so why is the gauge using the head temp for coolant temp, i need help. thanks.