What is the correct way to fill the radiator of a chevrolet venture The low coolant light came on then started flashing but the radiator is full of water but has no anti freeze is this the problem

No. The most common problem with the low sensor light is the switch which is located in the radiator just below the filler neck. First make sure that the radiator is full. With the cap off, start the engine and then add coolant to the radiator. There are two bleed valves in the system. One by the thermostat area and the other by the by-pass hose close to the water pump. Be sure all the air is out of the system. The low coolant sensor gets dirty and causes this problem.

The low coolant light is operated by a level sensor located in the coolant reservoir itself. If the low coolant light is on and the coolant level is full then wither the sensor is unplugged or the sensor is bad.

The coolant level sensor is located on the passenger side of the radiator, just below the bottom of the battery. If the light comes on, you'll need to fill the plastic coolant tank. But you also need to remove the radiator cap and fill the radiator itself. Only open the radiator when the engine is cold. If the radiator is full, and you are positive it's full, then the sensor needs to be replaced.

most cars and trucks have a censor on radiator or fill tank,ck the coolant level and if it is full then censor should turn lights off if it is low fill with water to full line and light should turn off

Check the coolant reservoir and the radiator for proper coolant level. If low you probably have a leaking intake gasket or possibly a head gasket leak. The intake leak will be visible on either end of the intake manifold, located at the very top portion of the engine. The head gasket usually shows up at the rear head, nearest the belt. You could have a water pump leaking and this would show coolant on the ground under the right front of the engine, more so when the engine is running. They are very common for all 3 problems.

Change the low coolant sensor. It is located on the radiator. It might be a good idea to get the radiator flushed too.

The low coolant level sensor is in the radiator below the fill neck it is a square looking box clipped into radiator it needs to be replaced if you are full of coolant and light is still on.

you need to check the coolant in the radiator, not just in the overflow tank, you are describing a low coolant problem, the thermostat could be the resign you have no heat but it would not explain the low coolant light, remove the radiator cap ( only when the engine is cold ) and start the engine with the cap off and then fill up the radiator........HAVE FUN

You may be low on coolant - or have an air bubble in the heater core! Make sure you have the right antifreeze and mix 50/50 with water. Start car, turn heater on max heat full blast and fill reservoir with coolant. If you have access to the radiator cap I would fill from there. This is a pressurized system, so it may blow some coolant out at you. Squeeze upper radiator hose to ensure it is full, cap radiator and now recheck the reservoir. If this doesn't help, you'll need to raise the front of the vehicle so the radiator cap is above the heater core hoses. Remove cap, start engine with heater and blower on high and fill radiator. Cap radiator before you lower the car and you should be good. Keep an eye on the coolant reservoir as you may have a leak which would cause the low coolant symptom. You also have a sensor to tell you is you are low on coolant. If you are and it is not lighting up, you may want to have it ( the sensor) tested and replaced.
Good luck!!

Check the coolant top up reservoir. Low coolant sensor is usually in the overflow/reserve container.
Wash out and clean any dirt or corrosion from the sensor prong.
Refill to correct level with fresh coolant, then recheck alarm operation.