First, the analog gauge is not always a true representation of the coolant temp as most analog gauges do not show a true linear display. What does the digital gauge read in different driving conditions? For example what range of temps are displayed in heavy city stop-and-go traffic? What about freeway cruising? On my 92, in city traffic, I see anywhere from 195 to 220 before the fans come on. On the freeway, it's usually 195-205.
Turning on the A/C will force the secondary fan to come on. You can actually cool the water temp down but running the A/C!
Each gauge has it's own temp sensor so there is an outside chance that the analog sending unit may be bad. The coolant fans are controlled by relays which are operated by the ECM. The fans will turn on and off at preset temps. Sometimes the relays will go bad. Fortunately they are inexpensive and easy to replace. I don't know what the exact temp is for the ECM to signal turning the aux fan on, but it's somewhere around 238 degrees. The fan should turn off around 185-190.
One problem with effective cooling is having the front of the radiator becoming clogged with debris. The air is brought in from under the car so leaves, paper, dogs, small cars are easily sucked up into the opening. Look up under the car behind the front license plate to see if anything is stuck up there. You will see the A/C condensor from the outside but to look at the front of the radiator, you will have to look thru the gaps in the radiator shroud on the right side after opening the hood. You can use a soft stream of water to push stuff back out from between the radiator core rows and fins.
Another possibility is a bad thermostat; it could be sticking or simply not working at all. I would have the cooling system flushed and install new green (ethelyne glycol) coolant in a 50/50 mix with distilled water and at the very least, have the radiator hoses replaced and possibly add a new thermostat. You can go to a lower temp 'stat like a 180 degree.
If you like to do work on your car, I would recommend getting the GM factory service manual You can find them on eBay or go to
www.helminc.com and order a set. They are the same ones that GM techs use and are well written and easy to understand. The parts store books like Haynes or Chilton are not vey clear as most of them cover a range of years. The factory manuals are year-specific.
