My husband put a new radiator in my daughter’s 1999 Volvo and now the radiator light comes on each time she starts the car. Although it goes off in a few minutes, I wonder if this is a computer issue…is the car’s computer confused because there is a new radiator but there is nothing “notifying the computer” it is there? It seems to be working fine in all other ways.
I think you MAY have air in the coolant causing this light.
Ensure the rad is full and run the engine and try to get any air out of the coolant.
You can remove the rad cap (engine COLD), idle the engine and watch for air bubbles to show and pop or leave the rad cap on and loosen the top rad hose and work a screwdriver under the end of the hose to get the air out.
Which specific radiator light? Those lights have specific meanings which are usually described in your owner’s manual. Some vehicles have lights that come on when the car is started that indicate that the engine is still cold. It goes off in a minute or two when the engine gets warmer. Many people consider that particular light to be useless. It usually looks like a thermometer.