Light on by fuel gauge (arrow shape going downward) 1999 sunfire pontiac

It's probably the float on the fuel pump.pull the pump and clean or just replace the fuel pump and float.

ECOTEC engine?? must use in line gauge to test

Sounds to be the dash itself. there is a chip in there and it sounds like it shorted out. You have to replace the panel. Junk yard would be best and cheapest.

Low coolant warning lamp.

check fuses,remove sender unit from tank,connect ohm meter to it and physically move arm up and down slowly and check for increase/decrease in resistance,if this is ok then supply power to the wiring to gauge and see if the needle rises,if no change in resistance sender is rooted,if no change in gauge when it is supplied power then the gauge is rooted,when diagnosing electrical probs always check fuses firstelectrical

One of two problems, your fuel level sending unit is defective, or your gauge Is bad.

your fuel pump is going out.

in the fuel tank

Hello mcammdf.
To properly test the fuel gauge circuit you will need to check the purple wire at the connector to the fuel tank.
Run a wire from the purple wire at the connector to body ground. If the gauge moves when you ground it the circuit to that point is good.
These cars are noted for fuel gauge problems and most probably the issue will be the sending unit in the fuel tank.

KL

does it look like a radiator? Low coolant sensor, may be in the overflow tank. Check your coolant levels when cold.