2004 Buick Regal temperature light came on, went off, came back on, did this several times. What could be the problem?

Your coolant is probably just a little low. When the coolant is sent through the cooling system to keep the engine temp down, the sensor that monitors coolant level notices that there is not enough in the radiator or overflow to meet factor specs (as the car heats and cools) this is why the light comes on and then goes off. It also could be another simple issue like the thermostat is going out ($10 approx) I would check the coolant level (when the car is COLD, do not open when its hot or you'll burn yourself). Best of luck and let me know if you need further tips or troubleshooting ideas.

Check the fluid level at the reservoir - DO NOT OPEN THE RADIATOR CAP WHEN THE CAR IS HOT! The reservoir has two lines on it - one a hot level and one for a cold level. Check at either engine status and add 50/50 mix of coolant and water until the reservoir is filled to the appropriate line (hot or cold).

I think you might have a faulty temp sending senor

car only has a light for over heating??? no temp gauge?

start with all your fuse and relays , maybe even the dash light bulb its self

See if your cooling fans Behind the radiator are working properly. If the warning light only comes on when you are driving slow or at at stoplight, this could be your problem. Check to see how much heat is actually in the engine compartment when that warning light turns on. If you can touch the top of the engine and the top radiator hose easily without burning your fingers, that engine is running cool, and it's probably only a sending unit. Find someone with an infrared hand held thermometer to get an accurate temperature reading. You did check the coolant level didn't you? If it's low start searching for the leak.